Internet Engineering Task Force Mike Kallas(Editor) INTERNET DRAFT Nortel Networks <draft-ietf-megaco-otherpkgs-00.txt> Zacharias Bilalis(Editor) Category: Standards Track(?) Siemens Expires: July 20, 2000 Contributions from: Klaus Hoffmann Siemens Klaus Pulverer Siemens Peter Blatherwick Nortel Networks Bob Bell Cisco Systems Markku Korpi Siemens Nancy Greene Nortel Networks Tom Taylor Nortel Networks Richard Bach Nortel Networks Christian Ruppelt Siemens Gunnar Hellstrom Omnitor James Rafferty Brooktrout Technology Glenn Parsons Nortel Networks Roy Spitzer Telogy Jinchi Chu Nortel Networks MEGACO Packages Not Included In MEGACO/H.248 White Draft STATUS OF THIS MEMO This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Bilias, Kallas [Page 1]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 ABSTRACT This document is work in progress. It gathers together all packages that have not yet been included in Annex E of Megaco/H.248 White Draft. It proposes additional text for MEGACO/H.248. This document is expected to be used at the Adelaide IETF meeting. TABLE OF CONTENTS 1 FAX/Textphone/Modem Tones Detection Package .. .. .. .. .. 3 2 Dynamic Tone definition package .. .. .. .. .. .. .. .. .. 4 3 NAS Package .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 6 4 Announcement PACKAGE .. .. .. .. .. .. .. .. .. .. .. .. .. 9 5 Signal Processing Network Equipment (SPNE) Package .. .. .. 10 6 Display Package.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 13 7 Key Package .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 16 8 Keypad Package .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 17 9 Label Key Package .. .. .. .. .. .. .. .. .. .. .. .. .. .. 18 10 Function Key Package .. .. .. .. .. .. .. .. .. .. .. .. .. 19 11 Indicator Package .. .. .. .. .. .. .. .. .. .. .. .. .. .. 21 12 Soft Key Package .. .. .. .. .. .. .. .. .. .. .. .. .. .. 22 13 Ancillary Input Package .. .. .. .. .. .. .. .. .. .. .. .. 24 14 Text Conversation package .. .. .. .. .. .. .. .. .. .. .. 25 15 Text Telephone package .. .. .. .. .. .. .. .. .. .. .. .. 30 16 Call Type Discrimination package .. .. .. .. .. .. .. .. .. 40 17 Fax package .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 49 18 MoDem package ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. 53 19 References .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 57 20 Author's Addresses.. .. .. .. .. .. .. .. .. .. .. .. .. .. 59 Bilias, Kallas [Page 2]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 1 FAX/TEXTPHONE/MODEM TONES DETECTION PACKAGE PackageID: ftmd, 0x0020 Version: 1 Extends: tonedet version 1 This package defines an event to detect the presence of data traffic (fax, textphone or modem) on a line. The main intention of this event may be used to effect the compression option on the line so that an audio codec capable of transmitting modem signals can be invoked to han- dle the connection when needed. This Package extends the possible values of tone id in the "start tone detected" event. Additional detectable tone id values: dtfm, 0x0039 This tone id is generated when the following tones are detected. For Fax: CNG; a T.30 fax calling V21flag, a V21 tone and flags for fax answering For Text CIV18; a V.8/V.18 CI XCI; a V.18 XCI V18txp a V.18 txp signal Belltone a Bell 103 carrier, either the high or the low frequency channel Baudot a Baudot initial tone and character Edt an EDT initial tone and character For Data CIdata a V.8/data CI Common to Voice and Text Dtmf a DTMF signal Common to Text and Data CT a V.25 calling tone V21tone a V.21 carrier either the high or the low frequency channel V23tone a V.23 carrier either the high or the low frequency channel Common to Fax, Text and Data V8bis a V.8 bis modem handshaking signal ANS or CED V.25 ANS, equivalent to T.30 CED from answering terminal ANSAM V.8 ANSAM Bilias, Kallas [Page 3]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 2 DYNAMIC TONE DEFINITION PACKAGE PackageID: dtd, 0x0021 Version: 1 Extends: None This package defines a mechanism to redefine existing tones and create new tones for playback. The existing tones are the ones described in supported packages that extend the tonegen generic package. 2.1 Properties Tone ID PropertyID: tid (0x0001) Description: Indicates the new or existing tone to be modified or who's tone string is to be read. Type: expanding enumeration Possible Values: Existing tone ids described in supported packages that extend tonegen or new tone ids to be added. Defined in: TerminationState. If the termination is in a context. The changes to the tones apply only to the termination in the context. When the termination leaves the con- text. The changes are lost. If the termination is in the null context, the changes apply to the termination from then on. If the termination is root, the changes apply to the whole gateway. Characteristics: both read and write. Tone String PropertyID: tst (0x0002) Description: Tone description string. Described later Type: String Possible Values: grammar described later. Defined in: TerminationState. Characteristics: both read and write: Note: If you write to tid, you can then set tst to a new value or read the current value in tst. If you read tid you get a list of the existing and new tones. To modify or create a new Tone: 1- set tid to an existing or new tone id Bilias, Kallas [Page 4]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 2- set tst to the new tone description if tst is null the id is decommissioned and removed. Only newly defined tonids can be removed. To read the list of tones defines: 1- read tid To read an already defined tone string: 1- set tid 2- read tst Some package-defined tones may not have a tone string in the gateway. In that case the tst read will have the value "Not Available" Tone String (tst) description: The syntax for the tone definition string is recursive and uses parenthesis as a delimiter of elements. DefToneString below is the tone string(tst) DefToneString = "(" DefToneElement ["*" RepeatCount ] ")" [","/"+"/"X" DefToneString] NOTE: a separator of ',' indicates that the next definition follows sequentially in time; a separator of '+' indicates that the following tone is to be mixed with the previous tone and is simultaneous with it; a separator of 'X' indicates that the first tone is modulated by the second tone. NOTE: All implementations must support sequential definitions (',' separator). Mixing ('+') and modulation ('X') support are optional, how- ever the implementation must make a best effort and return no error in these cases. NOTE: Recursion is limited to a maximum of 32 Levels. All implementa- tions must support at least 2 levels of recursion. RepeatCount = %d1-32767 / %d0 NOTE: repeatcount of 0 indicates infinite repeating. DefToneElement = ToneName ["," ToneDuration [ "," ToneAmplitude ]] ToneName = Tone id / "#"FreqValue / "&"AnnouncementParameterList Tone id = 1*VCHAR; Unique tone identity string or value FreqValue = %d0-4000; in Hertz AnnouncementParameterList = AnnouncementID ["," SubstitutionString] AnnouncementID = 1*VCHAR; Unique identifier for an audio announcement SubstitutionString = """1*VCHAR"""; a TTS string to be inserted into an announcement. ToneDuration = %d1-32767 / %d0 ; In Milliseconds NOTE: ToneDuration of 0 indicates infinite duration or duration defined by the Tone id. Bilias, Kallas [Page 5]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 ToneAmplitude = "-"%d32-1 / %d0; In dBm0 An examples of some tone definitions follows. ReorderTone = ((((#480)+(#620)),250,-24),(sil,250))*0 SITTone = (#950,330,-24), (sil,30), (#1400,330,-24), (sil,30), (#1800,330,-24), (sil,30) NumberYouHaveDialed = (SITTone), (&NumberDialed,"555-1234") Note: above tone definitions are from SR-TSV-002275. 2.2 Events None 2.3 Signals None 2.4 Statistics None 2.5 Procedures None 3 NAS PACKAGE PackageID: nas, 0x0022 Version: 1 Extends: none This package supports the functionality of a Media Gateway as NAS (Net- work Access Server). This encompasses the support of dial-in access to the NAS, but not the contact to a AAA server for authentication, author- ization, and the possible subsequent set-up of a layer 2 tunnel to a remote NAS. Those are autonomous functions of a NAS and therefore out of scope for the Megaco protocol (see e.g. IETF RFC 2661 (L2TP) and RFC 1661 (PPP)). 3.1 Properties VPN id Bilias, Kallas [Page 6]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 PropertyId: vpnid (0x0001) Description: identifies VPN Type: integer Possible Values: vpnid Defined in: Termination State 3.2 Events NAS Failure EventID: nasfail (0x0001) Description: Signals on the termination the detection of a failure due to external or internal (in the Media Gateway) reasons. EventDescriptor Parameters: streamid ParameterID: strid (0x0001) Description: ID of the stream being reported on. Type: integer Value: streamID ObservedEventDescriptor Parameters: Error code ParameterID: ec (0x0002) Description: describes the failure reason Type: 2 bytes Possible values: Default: 0000 (internal error) Authorization succeeded EventID: authsucc (0x0002) Description: This event signals that authorization by the AAA server for the requested service was successful (see for example IETF RFC 2138 (RADIUS)) EventDescriptor Parameters: streamid ParameterID: strid (0x0001) Description: ID of the stream being reported on. Type: integer Value: streamID ObservedEventDescriptor Paramters: none Bilias, Kallas [Page 7]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Authorization denied EventID: authden (0x0003) Description: This event signals that authorization by the AAA server for the requested service was denied (see for example IETF RFC 2138 (RADIUS)). EventDescriptor Parameters: streamid ParameterID: strid (0x0001) Description: ID of the stream being reported on. Type: integer Value: streamID Call back Request EventID: cbr (0x0004) Description: The call back event is used to notify that a call-back has been requested by the AAA server during the initial phase of a data connec- tion (see IETF RFC 2138 (RADIUS)). The event report includes the iden- tification of the user to be called back, e.g. E.164 number. EventDescriptor Parameters: ParameterName: streamid (0x0001) ParameterID: strid Description: ID of the stream being reported on. Type: integer Value: streamID Authentication Authorisation and Accounting (AAA) Failure EventID: aaafail (0x0005) Description: Used to signal failure of the AAA server. EventDescriptor Parameters: ParameterName: streamid ParameterID: strid (0x0001) Description: ID of the stream being reported on. Type: integer Value: streamID 3.3 Signals None Bilias, Kallas [Page 8]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 3.4 Statistics None 3.5 Procedures none 4 ANNOUNCEMENT PACKAGE PackageID: an, 0x0023 Version: 1 Extends: None That package supports announcement functionality at a Media Gateway 4.1 Properties None 4.2 Events Announcement completed EventID: ac (0x0001) Description: Indicates the completion of the announcement. EventDescriptor parameters None ObservedEventDescriptor parameters None Announcement failure EventID: af (0x0002) Description: Indicates the failure of the announcement. EventDescriptor parameters None ObservedEventDescriptor parameters Bilias, Kallas [Page 9]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 None 4.3 Signals Announcement play SignalID: ap (0x0003) Description: Initiates the play of an announcement Parameters: Signal type ParameterID: t (0x0001) Type: enumeration of announcements. Default is TO Duration ParameterID: d (0x0002) type: integer. Duration is ignored Specific numbers ParameterID: sn (0x0003) Type: integer Values: any Default is provisioned for every announcement. 4.4 Statistics None 4.5 Procedures None 5 SIGNAL PROCESSING NETWORK EQUIPMENT (SPNE) PACKAGE PackageID: spne, 0x0024 Description: This package contains parameters as defined in ITU Recom- mendation Q.55, SIGNALLING BETWEEN SIGNAL PROCESSING NETWORK EQUIPMENT (SPNE) AND INTERNATIONAL SWITCHING CENTRES (ISC), that specifies con- trol messages used between an International Switching Exchange and Sig- nal Processing Network Equipment (SPNE). SPNE's include echo control, noise reduction, automatic level control, frequency equalization, and A-law to Mu-law converters. SPNE functionality may be included in a MG and should be controllable by the MGC. Version: 1 Bilias, Kallas [Page 10]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Extends: DS0 Package version 1 5.1 Properties Non-Linear Processor PropertyID: nlp (0x000b) Description: non-linear processor property Type: enumeration Possible Values: "on", "off". The default is "off" Defined in: LocalControlDescriptor Characteristics: Read/Write Comfort Noise Injection PropertyId: cn (0x000c) Description: The media gateway may inject comfort noise on the termination. Type: enumeration Possible Values: "on", "off". The default is off. Defined in: LocalControlDescriptor Characteristics: Read/Write Automatic Level Control PropertyId: alc (0x0010) Description: The media gateway may perform automatic level control. The ALC type is determined and configured by manufacturer and/or carrier and is outside the scope of this Recommendation. Type: enumeration Possible Values: "off", "type0", "type1", "type2", "type3". The default is "off." Defined in: LocalControlDescriptor Characteristics: Read/Write Frequency Equalizer PropertyId: fe (0x0020) Description: The media gateway may perform frequency equalization. The FE type is determined and configured by manufacturer and/or carrier and is outside the scope of this Recommendation. Type: enumeration Possible Values: "off", "type0", "type1", "type2", "type3". The default is "off." Defined in: LocalControlDescriptor Characteristics: Read/Write Noise Reduction Device PropertyId: nrd (0x0030) Description: The media gateway may perform noise reduction on a call. The NRD type is Bilias, Kallas [Page 11]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 determined and configured by manufacturer and/or carrier and is outside the scope of this Recommendation. Type: enumeration Possible Values: "off", "type0", "type1", "type2", "type3". The default is "off." Defined in: LocalControlDescriptor Characteristics: Read/Write A-Law to mu-Law Conversion PropertyId: amc (0x0040) Description: The media gateway may perform A-law to mu-law conversion. Type: enumeration Possible Values: "off" : conversion not used "mutoa": Indicates mu-law to A-law conversion "atomu": Indicates A-law to mu-law conversion The default is "off." Defined in: LocalControlDescriptor Characteristics: Read/Write 5.2 Events Disabling Tone EventID: dt (0x0001) Description: This event is triggered when the echo canceller equipment detects in-band disabling tone. This implies looking for both 2100 Hz and 2100 Hz with 180 degree phase reversal. EventsDescriptor Parameters: None ObservedEventDescriptor Parameters: ParameterName: tone ParameterID: tone Type: enumeration Possible Values: "2100": Indicates a 2100Hz tone "2100rev": Indicates a 2100 Hz tone with 180 degree phase reversal 5.3 Signals None 5.4 Statistics None Bilias, Kallas [Page 12]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 5.5 Procedures None 6 DISPLAY PACKAGE PackageID: dis, 0x0025 Version: 1 Extends: None This package defines properties and signals associated with text display user interface elements. 6.1 Properties Number of rows PropertyID: nrows (0x0001) Description: Maximum number of rows on the display Type: integer Defined in: TerminationState. Characteristics: read only: Number of columns PropertyID: ncols (0x0002) Description: Maximum number of columns on the display Type: integer Defined in: TerminationState. Characteristics: read only: Supported unicode code pages PropertyID: cdpgs (0x0003) Description: a list of supported unicode pages Type: list of enumerated type Defined in: TerminationState. Characteristics: read only: Example: if the text display element supports U+2500 ->U+25ff, U+2600 ->U+26ff and U+2700 -> U+277f, this property would return "250, 258, 260, 268, 270" in cdpgs. Unicode page U+0000 -> U+00ff shall be supported in all implementations. Cursor row position PropertyID: cr (0x0004) Type: integer Defined in: TerminationState. Bilias, Kallas [Page 13]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Characteristics: read and write: Cursor column position PropertyID: cc (0x0005) Type: integer Defined in: TerminationState. Characteristics: read and write. Note: row and column numbering begin at 0. A display's origin is row 0, column 0. The origin is at the top left corner 6.2 Events None 6.3 Signals Display SignalID: di (0x0002) Description: Display text Parameters Row ParameterID: r (0x0001) Type: Integer Default is current cursor position Column ParameterID: c (0x0002) Type: Integer Default is current cursor position String ParameterID: st (0x0003) Type: String Default is empty Attribute ParameterID: a (0x0004) Type: enumerated or list of enumerated Possible values: plain, blink, invert, underline Default Value: Plain Note 1: Text will be inserted beginning at the row and column given in the signal parameters, relative to 0,0. If no row and column parameters Bilias, Kallas [Page 14]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 are given, the text will be inserted starting at the current cursor position. The current cursor position will always be advanced to the position immediately after the last character inserted. Note 2: The attribute parameter will apply to all characters contained in the signal. If no attribute is provided, plain text will be displayed. To turn on an attribute in the middle of a string, one would send a signal with a beginning sub-string of plain text, follow by a signal with the desired attribute(s) for the middle sub-string, and fin- ishing with the signal containing the remaining sub-string of plain text. Note 3: A string will not word wrap to the next row. If a string cannot fit into the current row, it will be truncated without warning. Clear Display SignalID: cld, 0x0002 Description: This signal clears the entire display and resets the current cursor position to the origin (row 0, column 0). Parameters: None 6.4 Statistics None 6.5 Procedures Unicode is supported to provide for multiple languages. The Unicode Standard, Version 2.0 or ISO/IEC 10646-1:1993 [xxx] shall be the defini- tive standard intended when the term Unicode is used within the context of this document. All text display elements shall at least support the Unicode pages U+0000 -> U+00ff as the basic character set. All text strings shall be encoded using UTF-8 as defined in ISO/IEC 10646 AM1 [xxx]. In the Display signal, text will be inserted beginning at the row and column given in the signal parameters, relative to 0,0. If no row and column parameters are given, the text will be inserted starting at the current cursor position. The current cursor position will always be advanced to the position immediately after the last character inserted. Carriage return <Unicode U+000D> is supported in-string, and moves the Bilias, Kallas [Page 15]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 text input to the beginning of the next line, clearing the remainder (if any) of the current line. Text wrapping is not provided. A string will not word wrap to the next row. If a string cannot fit into the current row, it will be truncated without warning. The attribute parameter applies to all characters contained in the current signal. If no attribute is provided, plain text will be displayed. For example, to turn on an attribute in the middle of a string, one would send a signal with a beginning sub-string of plain text, follow by a signal with the desired attribute(s) for the middle sub-string, and finishing with the signal containing the remaining sub- string of plain text. 7 KEY PACKAGE PackageID: key, 0x0026 Version: 1 Extends: none This package defines the basic behavior of key user interface elements. Specific key IDs are selected by name (keyid) from the list of keys. This package does not specify parameter values for keys. Intended to be extended by other packages which have key behavior. 7.1 Properties None. 7.2 Events keydown EventID: kd (0x0001) Detects dialpad key was pressed. EventDescriptor parameters: None. ObservedEventDescriptor parameters: Bilias, Kallas [Page 16]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 keyid (0x0001) Type: Enumeration Possible values: No values are specified in this package. Extensions to this package add possible values for keyid. keyup EventID: ku (0x0002) Detects dialpad key up. EventDescriptor parameters: None. ObservedEventDescriptor parameters: Keyid (0x0001) Type: Enumeration Possible values: No possible values are specified in this package. Extensions to this package would add possible values for keyid. Duration (0x0002) Type: integer Units: miliseconds Description: Key press duration (key down to key up). 7.3 Signals None 7.4 Statistics None 7.5 Procedures None 8 KEYPAD PACKAGE PackageID: kp, 0x0027 Version: 1 Extends: key version 1 This package defines the keypad user interface element. The keypad Bilias, Kallas [Page 17]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 package is used to represent a standard 10 digit key pad plus the '*', Additional keyid values: Name Description k0 Keypad digit 0 k1 Keypad digit 1 k2 Keypad digit 2 k3 Keypad digit 3 k4 Keypad digit 4 k5 Keypad digit 5 k6 Keypad digit 6 k7 Keypad digit 7 k8 Keypad digit 8 k9 Keypad digit 9 k* Keypad digit * k# Keypad digit # kA Keypad digit A kB Keypad digit B kC Keypad digit C kD Keypad digit D 8.1 Additional Properties: None 9 LABEL KEY PACKAGE PackageID: labelkey, 0x0028 Version: 1 Extends: key version 1 This package defines the basic behavior of labeled key user interface elements. Key labels may be used, for example, to provide information to the MGC regarding pre-configured telephone key assignments, allowing telephone moves and changes outside the initial administrative domain without requiring re-configuration of keys. May also be used to provide static label information on the telephone user interface, identifying key function to the user without the need for manual labeling. Specific keys are addressed by name (keyid) from the list of keys. This package does not specify parameter values for keys. Bilias, Kallas [Page 18]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Intended to be extended by other packages which have key behavior. 9.1 Properties Keylist (0x0001) Type: String, using the following format {{keyid, label, label_size}, ...} [[Editors note: Use ABNF definition]] Description: Keylist property allows auditing and setting of keyid/label mapping. Label size is also given. This package defines syntax only; no specific keys are defined. See derived packages for the actual lists. 9.2 Signals [[ Note: this signal left from previous versions to show alternate Signals- based approach to label update. Now moved to properties section for consistency. Comment welcome on which approach is better. ]] setlabel SignalID: sl (0x0001) Parameters: keyID (0x0001) Type: Enumeration. Possible values: From keyid list above. label (0x0002) Type: String Description: Can be used to identify the intent of the function key, as assigned by the MGC or by provisioning. The label may be used, for example, to implement self-labeling keys. 9.3 Procedures None. 10 FUNCTION KEY PACKAGE PackageID: kf, 0x0029 Version: 1 Bilias, Kallas [Page 19]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Extends: labelkey version 1 Common telephone function keys are defined in this package. This allows, for example, line keys to be implemented without specific knowledge of the physical layout of the telephone. Function keys may have well known names (keyid) associated with func- tion, for example "hookswitch", "hold", etc. Function keys may also be assigned a label identifier by the MGC. Additional keyid values in keyup and keydown events: Name Description kh Hookswitch kl Hold kc Conference kt Transfer kl001 - kl999 Set of line keys kf001 - kf999 Assignable function keys 10.1 Procedures Function keys may have well known names (keyid) associated with func- tion, for example "hookswitch", "hold", etc. These well know names identify the purpose of the particular key on the actual device. Func- tion keys may also be assigned a label identifier by the MGC. This approach avoids assumptions and/or the requirement for application level knowledge of device-specific configuration of the physical resources to derive intended function of keys. Function Keys can be co-related with physically associated Indicators using Function Key keyid and Indicator indid. If the IDs are identical, the MGC application can safely assume that the key and indicator are physically (or otherwise) associated on the actual device. Again, this avoids assumptions and/or the requirement for application level knowledge of device- specific layout of the physical resources. See also the Indicator package (ind). NOTE: The key sense of hookswitch (keyid=kh) is a special case. Key up indicates the hookswitch is depressed (i.e. handset is nominally on hook). Key down indicates the hookswitch is lifted (i.e. handset is nominally off hook). This allows for sensible use of the duration parameter in the keyup event which will normally give the duration the handset was off-hook. Bilias, Kallas [Page 20]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 11 INDICATOR PACKAGE PackageID: ind, 0x002a Version: 1 Extends: None This package defines the basic behavior of indicator user interface ele- ments. Specific indicators are addressed by name (indid) from the list of indicators. Indicators may have well- known names (indid) associated with function, for example "message waiting", "hold", "line active", etc. This allows, for example, indicators to be implemented without specific knowledge of the physical layout of the telephone. Intended to be possible to extend by other packages which have indicator behavior. 11.1 Properties Indicatorlist (0x0001) Type: String, using the following format {{indid, label, label_size}, ...} [[Editors note: Use ABNF definition]] 11.2 Events None 11.3 Signals SetIndicator SignalID: is (0x0001) Set indicator state. Parameters: indid (0x0001) Type: Enumeration. Possible values: Name Description il Hold ic Conference il001 - il999 Set of line indicators if001 - if999 Assignable function indicators Bilias, Kallas [Page 21]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 ir Ringer/Alerter indication im Message waiting indicator state (0x0002) Type: Enumeration. Possible values: On, off, blink, fast_blink, slow_blink. Default is off. [[ Require separate audible alert package, to cover ringer and other audible alerts. ]] 11.4 Statistics None 11.5 Procedures Indicators can be co-related with physically associated Function Keys using Indicator indid and Function Key keyid. If the IDs are identical, the MGC application can safely assume that the key and indicator are physically (or otherwise) associated on the actual device. This avoids assumptions and/or the requirement for application level knowledge of device- specific layout of the physical resources. 12 SOFT KEY PACKAGE PackageID: ks, 0x002b Version: 1 Extends: labelkey version 1 Softkeys are a combination of a function key and a display user inter- face element, sharing some behavior of each. Softkeys are intended to be dynamically updated by the MGC, based on the current state and con- text of the application controlling the MG. Since the display aspect and the key aspect are explicitely bound together, this avoids assump- tions and/or the requirement for application level knowledge of device- specific layout of the physical resources. See Procedures for details. 12.1 Properties Number of softkeys PropertyID: nskeys (0x0002) PropertyType: Integer haracteristics: read only Bilias, Kallas [Page 22]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Defined in: TerminationState Description: Maximum number of individual soft keys. Display size PropertyID: sz (0x0003) Type: Integer Characteristics: read only Defined in: TerminationState Description: Maximum number of characters that can be displayed. Supported unicode code pages PropertyID: cdpgs (0x0004) Description: a list of supported unicode pages Type: list of enumerated type Defined in: TerminationState. Characteristics: read only 12.2 Signals SetDisplay SignalID: sd (0x0002) Description: Set softkey dynamic display content. Parameters: keyid (0x0001) ParameterID: k Type: Enumeration Possible values: sk1 - sk999 displayContent (0x0002) Parameter ID: d Type: String 12.3 Procedures The display aspect is a subset of the Display (dis) package. Unicode is supported to provide for multiple languages [xxx], and all SoftKey ele- ments shall at least support the Unicode pages U+0000 -> U+00ff as the basic character set. All text strings shall be encoded using UTF-8. If a string cannot fit into the display area, it will be truncated without warning. The key aspect, including Events and labeling, derives directly from Label Key and Key packages. Softkey identifiers (keyid) are indexed Bilias, Kallas [Page 23]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 1,2...N. N (nskeys) is the maximum number of softkeys supported by the MG implementation. Refer to the Label Key (labelkey) and Key (key) packages for further details. 13 ANCILLARY INPUT PACKAGE PackageID: anci, 0x002c Version: 1 Extends: none The ancillary input package is used to enter user alphanumeric informa- tion such as text input or scan data, which is forwarded to the MGC for processing. The information is presented as a Unicode character encoded in UTF-8 format [33]. 13.1 Properties None. 13.2 Events Character input EventID: ch (0x0001) Description: A character has been input. EventDescriptor parameters None ObservedEventDescriptor parameters: id (0x0001) Type: Character (UTF-8 character) 13.3 Signals None. 13.4 Statistics None. 13.5 Procedures Bilias, Kallas [Page 24]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 None. 14 TEXT CONVERSATION PACKAGE Package Name: Text Conversation PackageID: txc (0x0037) Version: 1 Extends: None Description: The Text Conversation package is intended for enabling real time text conversation between terminals in different networks or multimedia environments. This package includes the mechanisms needed to transport T.140 text conversation streams in multimedia environments. The tran- sport mechanism will be different for each environment where the package is used. 14.1 Properties Text buffering time PropertyID: bufftime (0x0001) Type: Integer Possible values: 0-500 Defined in: LocalControl Characteristics: Read/Write Description: This property indicates the time in ms that T.140 data shall be col- lected before transmission in order to keep overhead from text low. In low bitrate IP networks, a value of 300 ms is recommended. In environ- ments with low overhead or high bitrates this property should have the value 0 enabling immediate transmission of entered characters. Text termination connection state PropertyID: connstate (0x0002) Type: Enumeration Possible values: Idle for no connection efforts Prepare for being known in the termination and ready to accept connections Initiating for taking the initiative to establish a text connection Accepting for accepting an incoming request for a session Denying for denying an incoming connect request Connected for completed connection Defined in: TerminationState Characteristics: Read/Write Bilias, Kallas [Page 25]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Description: The connection state property is used to request a text connection, and reflect details of the achieved text connection. Parameters UserIdentity ParameterID: userid (0x0001) Type: String Possible value: String of up to 64 characters in Unicode UTF-8. Description: This parameter holds the optional User Identity parameter of a T.140 text conversation session. Transport ParameterID: trpt (0x0002) Type: Enumeration Possible values: H224 for H.224 Client ID=2 in H.320 AL1 for AL1 in H.324 TCP for TCP as in H.323 Annex G [18] RTP/T140 for RTP with T140 [19] as in H323 Annex G [18] or IETF SIP RTP/RED/T140 for RTP with T140 and redundancy coding RED as in H323 Annex G or IETF SIP T134 for T.134 in the T.120 environment [20] unassigned Description: The Transport parameter reflects the transport mechanism selected for the Text Conversation termination. Text Protocol Version ParameterID: proto (0x0003) Type: Integer Possible values: Any integer corresponding to a T.140 version number. (currently 1) Description: The version of the T.140 protocol used in the connection. Redundancy Level ParameterID: red (0x0004) Type: Integer Possible values: 0-6 0=use default or automatic decision on redundancy level (default) 1=Use no redundancy 2-6=use specified number of generations of data. Description: The number of generations to use in RTP redundancy coding including Bilias, Kallas [Page 26]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 the Primary. 14.2 Events Connection State Change Event Id: connchange (0x0001) ObservedEventDescriptorParameters ParameterName: Connection Change ParameterID: connchng Type: Enumeration Possible Value: As property txc/connstate Description: This event will occur when the text connection state for the termination has changed. Its parameter is the new contents of the Connection State property. 14.3 Signals None 14.4 Statistics Characters Transferred StatisticsID: chartrans (0x0001) Units: count Description: No of bytes of T140 data transferred through the termination. Lost Packets StatisticsID: packlost (0x0002) Units: count Description: Number of T140 packets lost as counted by the receiving T.140 termination. 14.5 Procedures The following are standard transport mechanisms for text conversation in different environments. * In H.320: H.224 with Client ID=2 * In H.324: AL1 channel connected with H.245 procedures * In T.120. T.134 transport in T.125 communication channel environment. * In H.323. RTP/T140 or TCP as selected with H.245 messages. * In IETF SIP: RTP/T140 as initiated with SDP. Note that the T140 text media is also used together with V.18 modems for text telephony, specified in a separate package: Text_Telephone (txp). The Text Conversation package is intended to be added to a multimedia termination, handling appropriate multiplexing and control. Bilias, Kallas [Page 27]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Function -------- A termination with Text Conversation adds capability declaration for a text conversation channel in the call setup according to procedures defined for each environment. When matching capabilities exist, a T140 channel is established according to the transport protocol used in the current environment. T140 text stream contents received from one termi- nation is transferred for transmission to other t140 capable termina- tions in the context. The T140 contents may be buffered for a short moment for possible collection of more text in the same transmission according to the buffer time property. Real time text conversation allows telecom users to carry out a written conversation. The presentation and coding aspects of standardised text conversation are defined in ITU-T T.140. Text is transmitted character by character or in small blocks so that the users experience a direct connection. The text and basic editing control is ISO 10 646-1, UTF-8 coded. Figure I/1 gives an example of how a text conversation can be displayed to the user. |------------------------------------------------------| | Anne | Eve | |------------------------------------------------------| |Hi, this is Anne. | | | |Oh, hello Anne, I am glad you | | |are calling! | |Have you heard that I | | |will come to Paris in |No, that was new to me. What | |November? |brings you here? | |------------------------------------------------------| Figure: Possible display of a one to one text conversation. For each transport environment, a suitable transport protocol must be selected to carry the text. Currently defined and Recommended transport environments for T.140 text media streams that can be supported by this package are: 1. Packet networks, where the procedures described in H.323 Annex G can be used to for setting up and conducting text conversation ses- sions, using TCP or RTP/T140 for the transport of T.140. 2. Packet networks, where the IETF Session Initiation Protocol SIP can be used for setting up and conducting text conversation sessions using RTP/T140 for the transport of T.140. Bilias, Kallas [Page 28]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 3. The H.324 multimedia environment in PSTN, ISDN and Mobile networks, where an AL1 channel connected by H.245 procedures is used for T.140. 4. The H.320 multimedia environment, where a H.224 channel with client ID=2 is specified for transport of T.140. 5. The T.120 data conferencing environment, that can be used alone or in conjunction with any of the environments above, where T.134 specifies the application entity and T.125 the data channel for T.140. A separate Text Telephone package (txp) supports text telephony in the PSTN using the ITU-T V.18 modem in native and legacy modes and T.140 for communication with terminations using this package. Interworking between these forms of Text Conversation can be achieved through the use of gateways with packages defined here. Total Conversation ------------------ Most text conversation transport environments are part of multimedia communication systems. With the introduction of text, they enable conversation in video, text and voice simultaneously, called Total Conversation. The total set of communication modes that people tend to use locally can be offered on a distance through Total Conversation. Since the text part is built on the unified presentation level T.140, the the task to arrange interoperability of Total Conversation in dif- ferent network environments through a gateway is simplified. Video is optional in the multimedia systems. Therefore compatible text- and-voice conversation can also be established within the same frame- work. Descriptor to use for text conversation. ---------------------------------------- One descriptor value is of specific interest for the Text Conversation and Text Telephone packages. That is the text conversation media stream. It is described here for information. Text conversation stream ------------------------ This descriptor is used for the text conversation stream, according to ITU-T T.140. T.140 gives a general presentation level description for a termination supporting real time text conversation. The text and basic Bilias, Kallas [Page 29]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 editing control is UTF-8 coded. For each transport environment, a suit- able transport protocol must be selected to carry the text. T140 is a registered MIME text stream name, that can be specified to be used as it is or in RTP embedding. Examples: >From MGC to MG in an ADD command, the T140 stream could be specified as this example shows: Media { Stream = 4 { LocalControl { Mode = ReceiveOnly, g/NetworkType = RTP/IP4, g/PreferredCodecs=T140}}} The MG would return the SDP specification for the media stream: Media { Stream = 4 {Local = SDP { v=0 c=IN IP4 125.125.125.111 m=text 1111 RTP/AVP 98 a=rtpmap:96 red a=fmtp: 98 96/96 a=rtpmap: 96 t140}}} 15 TEXT TELEPHONE PACKAGE PackageID : txp (0x0038) Version: 1 Extends: None Description: The text telephone package is used on a line termination in a Media Gateway, to handle text telephone calls. It includes V.18 text telephone modem functionality that adapts to different legacy text telephone sys- tems in the PSTN as well as it provides communication with V.18 equipped text telephones. The text media stream is UTF-8 coded with a few editing functions as specified in ITU-T T.140. 15.1 Properties Conversation mode PropertyID: convmode (0x0001) Type: Enumeration Possible values: Text-only; Basic text only mode, not possible to combine with voice. Alternating; Text and voice may be alternating. Bilias, Kallas [Page 30]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Simultaneous; Simultaneous text and voice mode. Defined in: Termination state Characteristics: Read/Write Description: The behaviour of the termination is influenced by this property. By setting the property to a selection of the possible values, the number of ways that the conversation can be conducted can be defined. After connection the property contains the actual conversation mode used in the call. The basic text only mode shall always be supported. The alternating text and voice mode is most often used to enable one user to speak and read and the other to listen and type. It is used because there was no technology support for simultaneous voice and text when text telephony was introduced. It is only supported for compatibil- ity with the legacy mode text telephone habits. The simultaneous text and voice mode enables the users to communicate in any combination and order of the two media. No legacy mode terminals operate in this mode. Communication Mode PropertyID: commode (0x0002) Type: Enumeration Possible values: V18-V21; native V.18 mode for text only or text and voice alternatively. V18-V61; native V.18 mode for text and voice simultaneously. V21Hi; legacy V.21 mode transmitting on the high channel V21Lo legacy V.21 mode transmitting on the low channel. DTMF; DTMF text telephone mode. EDT ; EDT ("European Deaf Telephone") Baudot 45; Baudot 45.45 bits / s Baudot 47; Baudot undetermined bitrate Baudot 50: Baudot 50 bits/s V23Hi V.23 modulation and Minitel coding transmitting on the high channel V23Lo V.23 modulation and Minitel coding, transmitting on the low channel. BellHi; Bell 103, transmitting on the high channel BellLo; Bell 103, transmittion on the low channel None; No mode achieved Defined in: LocalControl Characteristics: Read/Write Description: This property indicates what modulation and mode the V.18 modem is operating in, reflecting what type of text telephone it is in connection Bilias, Kallas [Page 31]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 with. For an explanation of the different modes, see ITU-T V.18. If specific mode operation is wanted, this property is set before the text connection is made. (to be used with care since it disables all automoding compatibility opportunities embedded in the V.18 concept) When a legacy mode textphone signal is detected in automode monitor mode, the connection result is only reported, but V.18 does not transmit any signal until ordered to do so. Connection Mode PropertyID: connmode (0x0003) Type: Enumeration Possible values: Idle: no connection established and no efforts to connect Automodecalling: actively seeking text contact as a caller, sending V.8 CI and V.18 XCI signals. Automodeanswer: actively seeking text contact as an answering part, sending probe signals in the different legacy modes. Automodemonitor: passively listening on the line for textphone signals without transmitting any stimulating signals, and only reporting observed textphone signals. Appendix3connect: automatically seeking between calling and answer modes as needed when entering text mode from voice mode during a call. Specificcalling; for direct request of the native or legacy mode indicated in the Communication Mode property. Specificanswering: for direct request of the native or legacy mode indicated in the Communication Mode property. Connected: connection established in one of the communication modes Defined in: Termination State. Characteristics:Read/Write Description: This property indicates in what connection phase mode the V.18 modem is operating. A connection effort is initiated by setting this property to the desired mode. A V.18 modem can be controlled to operate in one of a set of modes for seeking contact with a counterpart. The modes available are listed as values of this property Once connected, the termination operates in the selected mode until the text connection is lost or it is ordered to disconnect. If text connec- tion is lost for a certain time, the automoding procedure can be res- tarted or the modem can stay in the achieved mode trying to reconnect. Bilias, Kallas [Page 32]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 The automode monitor mode may be used on a connected voice line to detect if the remote user want to enter text mode. It must be noted that for some of the legacy modes (EDT, DTMF and Baudot), the user has to push some keys on the textphone to make the connection when V.18 is set in the automode monitor mode. This is slightly unusual for a text- phone user, who normally waits for the answering side to start the conversation. Therefore, the explicit automoding modes should be used when possible. Probe message PropertyID: probemsg (0x0004) Type: String Possible Value: Any string, not more than 20 characters long. Defined in: Termination State Characteristics: Read/Write Description: This property holds a short string that the termination transmits as a stimulating probe message for the carrierless communication modes in the answering modes. The far end user will see this message when it is transmitted in the mode matching the counterpart's textphone, and type a response back, enabling the V.18 modem to detect the type of carrierless text telephone in the connection. When issued, it is automatically followed by " GA" in Baudot probing, and with "+" in EDT and DTMF probing to reflect the turntaking signal habit in the different user communities. The string could be customised to briefly inform the called user about what service that is reached. Note that the string is not issued in the carrier modes. Probe order PropertyID: probeorder (0x0005) Type: Enumeration Possible values: (for the corresponding orders, see V.18) AUS; Optimised for Australia-Ireland; GER; optimised for Germany-Switzerland-Italy-Spain; NL; optimised for The Netherlands; SCAND; optimised for Scandinavian Countries; UK; optimised for UK ; US; optimised for USA-Canada; FR; optimised for France-Belgium. Any combination of none to six of the type indicators V21, DTMF, Baudot, EDT, MINITEL and BELL in the desired order; Defined in: Termination state Characteristics: Read/Write Description: Bilias, Kallas [Page 33]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 This property holds an indication on the order the probes will be transmitted. Probing is a time consuming procedure and it is important that the most likely modes are probed first. For simplicity, V.18 enumerates a set of suitable probe- orders for different geographical areas. For other areas the order to select depends on if any legacy mode textphones are on the market in the area. An optimised order can be com- posed by enumerating the desired specific type indicators. Note that leaving out a type from probing may cause connection problems for text- phones of that type. Action at loss of connection PropertyID: lossconnection (0x0006) Type: Enumeration Possible values: Keep: keep selected communication mode Return: return to automoding. Defined in: Termination State Characteristics: Read/Write Description: This property tells how the V.18 modem handles loss of text connection. When "Keep" is selected, the conversation is optimised for the alternat- ing text - voice mode. When "Return" is selected, the communication is optimised for call forwarding between different types of text tele- phones. V18 options PropertyID: v18opt (0x0007) Type: Enumeration Possible values: List of: V.61 capability: indicates the ability to use V.61 modulation V.8 bis capability: indicates the ability to use V.8 bis handshaking Defined in: Termination state Charateristics: Read/Write Description: This property indicates what optional capabilities the V.18 modem implementation has and is allowed to use. Character set PropertyID: characterset (0x0008) Type: String Possible values: ISO registered name for a character set. Defined in: Termination State Characteristics: Read/Write Description: The legacy modes have limited character sets. For all legacy modes, appropriate character conversion, filtering and control interception is Bilias, Kallas [Page 34]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 included in the package functionality, so that the communication with other T140 text terminations in the context is equalized to a T140 text stream.For a user friendly conversion of received national characters in the limited character sets to ISO 10 646-1 used in T.140, there is a need to specify what national translation table to use. This is valid for EDT, DTMF, V.21 and Baudot modes. The Character set parameter is the the registerd ISO code for the national variant of the ITU-T T.50 char- acter set used. Default is: * German for EDT, * Danish for DTMF (suitable also for the Netherlands), * Swedish/Finnish for V.21 (suitable also for UK), * International Reference Version for Baudot. An example: In Norway, the letter "" (A and E together) is used in the same location of the 7-bit character table as used for letter "" (A with umlaut) in Finland and Sweden. The international reference version has the character "[" (left bracket) in the same position. In T140 these characters have unique positions and the text telephone package must make the proper translation of received national characters into a unique ISO 10646 code depending on the target language. Initial characters PropertyID: initchars (0x0009) Type: String Possible values: Any string, maximum length 255 bytes. Defined in: Termination State Characteristics: Read/Write Description: The initial characters property can be used to insert characters received during detection and discrimination of call type with the Call Type Discrimination package. If inserted before connection in a specific mode is requested, the characters are returned first in the T140 text stream. This operation is intended to cater for the carrierless text telephone modes, where valid user data is consumed by the discrimination process. After successful connection through automoding, the initial characters are also available for reading in this property. The string is cleared at disconnection. 15.2 Events Connection mode changed EventID: connchng (0x0001) ObservedEventDescriptorParameters Same as the property txp/commode Description: This event reports the change of communication mode, as result of a Bilias, Kallas [Page 35]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 connection effort, or a disconnection. 15.3 Signals None. (the procedures to issue tones and signals are internal to the package and not available as named signals) 15.4 Statistics Number of characters transferred StatisticsID: chartrans (0x0001) Units: count Description: Number of bytes of T140 data transferred. Number of alternating turns. StatisticsID: altturns (0x0002) Units: count Description: Number of alternating turns when using alternating conversation mode. 15.5 Procedures Descriptors to use for text telephony: Two descriptor values are of specific interest for the Text Telephone package. That is the text conversation media stream and the V.18 modem. The text conversation media stream is described in the Text Conversation package. The V.18 modem descriptor is described here for information. V.18 Modem ---------- Modem name V18. This modem type is intended for communication with text telephones in the PSTN. It is embedded in the textphone package. Some properties of the text telephone package directly reflect parameters for control of the V.18 modem. V.18 modem implementations may have different capabili- ties reflected in the property values. A V.18 modem may be operated in automode monitor mode, when it listens on a voice line for text telephone signals. This mode can be used to detect that the user wish to transit from voice to text during a voice call. Alternatively, a V.18 modem may be operated in modes where it actively tries to establish a text telephone connection. The procedure includes Bilias, Kallas [Page 36]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 transmission of text telephone specific signals on the line. After successful connection in a text telephone mode, the text session is conducted in the specific mode and the text stream is made available in T.140 format for other text terminations in the context. The text telephone package only contains the text connection and text media aspects of the termination. It is supposed to be combined with appropriate call control packages, line interface packages and voice channel packages. Text Telephony -------------- Text Telephony offers a real time conversation in text between two par- ties. It may be combined with voice conversation. Text telephony in PSTN existed in at least 6 incompatible legacy modes before the automoding modem Recommendation for text telephony V.18 was introduced by the ITU. V.18 is suitable for use in PSTN text telephones, but also in gateways for connection to the PSTN text telephones. When connected, it can operate in one of its native V.18 modes, or in any of the 6 legacy modes described in V.18 annexes. The legacy modes are Baudot, EDT, DTMF, V.21, Minitel and Bell103. The mode detection and adjustment of the transmis- sion to the selected mode is automatic. The native modes use ITU-T T.140 for the text coding and control and V.21 or optionally V.61 for the modulation. The legacy modes use dif- ferent character coding schemes, but when used in a gateway, the text stream to and from the textphone termination is T.140 coded for all modes. The text telephone package described here includes character conversion, filtering and other adaptation needed for conversation with the legacy mode text telephones. Carrier modes and carrier-less modes. ------------------------------------- Three of the legacy textphone modes are carrier-less. This means that they do not send any signal at all when there are no characters to transmit. Three legacy modes and the native V.18 modes use a carrier tone transmitted as long as the connection is maintained. If the carrier stops, it is detected but the line is not disconnected, because this is normal behaviour during call transfer and alternating voice and text usage. Text telephone package considerations above the V.18 modem level. ----------------------------------------------------------------- V.18 only specifies an automoding modem and the requirement to use T.140 Bilias, Kallas [Page 37]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 when V.18 native mode is achieved in a connection. When used in a gate- way, there are some general issues that must be handled above the V.18 level. Character set: -------------- The legacy modes have limited character sets. For all legacy modes, appropriate character conversion, filtering and control interception is included in the package functionality, so that the communication with other T140 text terminations in the context is equalized to a T140 text stream. Embedded termination functionality ---------------------------------- There is no need to open all details of the use of V.18 and T.140 to be accessible from the MGC in a gateway. V.18, T.140, character conversion methods and other automated methods are therefore combined in the text telephone package that can be added to suitable terminations of a gate- way. This figure describes the text telephone package components. Text stream Control Audio stream | | | ------ | | __|T.140 |___ | | | ------ | | | ----------- ---------------- | | |Transparent| |T.140 conversion| | | | For native| | for legacy | | | | modes | | modes | | | ------+---- ---------+------ | | |----| |---------| | | ---- | | |V.18| | | ---- | | +--------------------+-----------+ Line Interface | Figure : Text telephone package components Basic operation --------------- Bilias, Kallas [Page 38]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 After line connection, the termination where the Text Telephone package is applied should be requested to try a text telephone connection using the functionality of the Call Type Discrimination Package for the modem signalling according to ITU-T V.18 in a selected mode. Once the connec- tion is established, this package is used for the text communication in the established mode. After connection in text mode, the result is a gateway context with one textphone termination and one voice line termination connected to the same line. In the same context, the normal case is to have IP connec- tions with one audio RTP termination and one RTP/T140 text termination. In the most simple text-only case, the audio streams are not used and may be released. Text received through the V.18 modem is converted if necessary to T.140. It is embedded in the RTP/T140 format according to the rules in T.140 and RTP/T140. Text received from the IP side is transmitted through the V.18 modem after extraction from the RTP packets. This process continues until any end disconnects. Operation with alternating text and voice mode ---------------------------------------------- If the involved gateways have the alternating text and voice capability, the following procedure can be applied to give the users a possibility to go back and forth between using text and voice. On the IP side, two streams are members of the context during the call, the text stream and the audio stream. The procedure is slightly dependent on the terminal type as described in the following section. Alternating text and voice mode with legacy, carrier-less textphones: --------------------------------------------------------------------- For the carrierless types Baudot, DTMF and EDT the following way to operate should be used: When V.18 detects text, the textphone termina- tion stops feeding the audio stream into the audio- RTP stream, and instead inserts the detected and T140 converted characters into the RTP-stream. This mode is continued as long as characters keep coming from the PSTN textphone. When no more characters arrive, and no textphone signal is received within 2 seconds, the audio channel is again fed to the RTP-Audio chan- nel. If new text comes from the V.18 side, the process is repeated. It is important that the implementation of V.18 can retrieve characters from the first detected text telephone signals after each mode shift. The leading tones before the characters can be as short as 150 ms. Bilias, Kallas [Page 39]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 If text is received from the remote end through the RTP-Text stream, when V.18 is not active receiving text, the voice path is muted, and the characters are sent to the V.18 modem for transmission. When all text is transmitted and no more is received for two seconds, the audio channels are enabled again. Since the carrier-less systems are one way alternate transmission sys- tems, transmission of characters is possible only in one direction at a time. Once started, reception is given priority. On the RTP side, two way simultaneous transmission is possible. There- fore, characters received from the RTP side while V.18 is busy receiving are buffered (up to a reasonable limit). All these actions after the initial connections are automatic and are handled within the textphone termination. Alternating voice and text conversation in carrier mode: -------------------------------------------------------- After a carrier mode text connection is established, loss of carrier can be taken as the indication that the RTP-Audio channel shall be con- nected with audio interface of the line. When the remote end is a V.21, Bell or V.18 device, the text communication can be full duplex, so the gateway can just let the text streams flow between the terminations. Minitel does not support any voice interworking mode. Simultaneous voice and text mode -------------------------------- In case the simultaneous voice and text method is enabled, the handling of the voice and text channels is trivial. Once connected, the text stream can stay connected with the remote text stream all the time to serve a two way simultaneous text conversation, and the audio channel can be connected with the remote audio stream to support a two way simultaneous audio channel. This mode can be supported by V.18 with V.61 modulation. 16 CALL TYPE DISCRIMINATION PACKAGE PackageID : ctyp (0x0039) Version: 1 Extends: none Description: This package monitors the termination for signals indicating presence of a T.30 telefax terminal [11], a V.18 or legacy mode text telephone [15] Bilias, Kallas [Page 40]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 or data modem. In co- operation with the MGC and the remote MG or end- point, it can perform exchange of signals until the call type is deter- mined and an appropriate mode for the call can be established. 16.1 Properties Initial characters PropertyID: initchars (0x0001) Type: String Possible values: Any string, maximum length 256 bytes. Defined in: Termination State Characteristics: Read/Write Description: The initial characters property can be used to retrieve characters received from carrierless text telephones of the Baudot, EDT and DTMF types. The characters are received up to the first gap in the carrier for Baudot and EDT, and the first DTMF tone for DTMF. They can be inserted in the txp package for a seamless takeover of a connection. Call Types PropertyID: ctyp (0x0002) Type: sub-list Possible values: FAX TEXT DATA VOICE Defined in: Termination State Characteristics: Read/Write Description: The Call Types property selects the types of calls for which the termination is monitored. Text Call Types PropertyID: ttyp (0x0003) Type: Sub-list Possible values: V21 DTMF Baudot45 Baudot50 Bell EDT Minitel V18 Description: This parameter indicates for what text telephone modes the termination is monitored. Bilias, Kallas [Page 41]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 V8bissupport PropertyID: v8bsup (0x0004) Type Boolean Possible values: True V.8 bis is supported by the package False V.8 bis is not supported by the package Defined in: Termination State Characteristics: Read Description: Support of the V.8 bis [14]modem negotiating procedure is optional. The V8bissupport property indicates if V.8 bis is supported. 16.2 Events Discriminating tone detected EventID: dtone (0x0001) Description: This event indicates that a signal valid for detection and discrimina- tion of mode was detected. The signal name is given as a parameter. Further logic is needed in some cases to discriminate the call type from this information. The V.8 bis related parameters are returned only when V.8 bis is supported. EventsDescriptor parameters: None ObservedEventDescriptor parameters: Parameter: Signaltype ParameterID: st (0x0001) Type: Enumeration Possible values: For Fax: CNG; a T.30 fax calling V21flag, a V21 tone and flags for fax answering For Text XCI; a V.18 XCI V18txp1 a V.18 txp signal in channel V.21(1) V18txp2 a V.18 txp signal in channel V.21(2) BellHi a Bell 103 carrier on the high channel BellLo a Bell 103 low channel Baudot45 a Baudot45 initial carrier and characters with characters in signalvalue Baudot50 a Baudot50 initial carrier and characters with characters in signalvalue Edt an EDT initial tone and characters Bilias, Kallas [Page 42]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 with characters in signalvalue For Data ASig Modulation signal from a mode only used for data. E.g. not V.21, V.23 and Bell 103. Common to Voice and Text: Dtmf a DTMF signal with value in signalvalue Common to Text and Data: CT a V.25 calling tone V21hi a V.21 carrier on the higher frequency channel V21lo a V.21 carrier on the low frequency channel V23hi a V.23 high carrier V23lo a V.23 low carrier CI a V.8 CI with contents in signalvalue Common to Fax, Text and Data: ANS or CED V.25 ANS, equivalent to T.30 CED from answering terminal ANSAM V.8 ANSAM CM V.8 CM with contents in signalvalue CJ V.8 CJ JM V.8 JM with contents in signalvalue ENDOFSIG End of reported signal detected (reported for continuous or repeated signals V8BIS V.8bis signal, with signal type in parameter V8bistype and value in signalvalue TIMEOUT A time for waiting for a signal elapsed Parameter: signalvalue ParameterID svalue (0x0002) Type: string Possible values: Information contained in the detected signal, coded as a string of octets. Parameter: valuelength ParameterID: vallen (0x0003) Type: Integer Possible values 0-80 Description: Length in octets of the parameter signalvalue. Parameter: V8bistype ParameterID v8bist (0x0004) Type enumeration Possible values Bilias, Kallas [Page 43]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 ESi V.8bis signal ESi ESr V.8bis signal ESr MRe V.8bis signal MRe MRd V.8bis signal MRd CRe V.8bis signal CRe CRd V.8bis signal CRd MS V.8 bis message MS with contents in signalvalue CL V.8 bis message CL with contents in signalvalue CLR V.8 bis message CLR with contents in signalvalue ACK V.8 bis message ACK with contents in signalvalue NAK V.8 bis message NAK with contents in signalvalue Description: A detected V.8 bis signal 16.3 Signals V8Signal SignalID: v8sig (0x0001) Parameters V.8 Signal Type Parameter ID v8styp (0x0001) Type Enumeration Possible values CM CJ JM CI Default may be provisioned V8SigCont Parameter ID v8scont (0x0002) Type string Possible values Allowed contents of the signals Default is empty Description The V.8 [13] signals carry data for call type and modulation modes. These parameters can be supplied through the v8cont parameter. V18XCIEnable Parameter ID: v18xcien (x0003) Type Boolean Possible values True XCI transmission enabled during V.18 CI transmission False XCI transmission disabled Default is False Description: XCI can be sent intermixed with CI transmission as specified in V.18 to stimulate plainMinitel terminals to respond as text telephones Bilias, Kallas [Page 44]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 AnswerSignal SignalID: ans (0x0002) Signal Type TO Parameters AnsType ParameterID AnsType (0x0001) Type: Enumeration Possible values: ANS V.25 ANS (equivalent to T.30 CED) ANSBAR V.25 ANS with phase reversals ANSAM V.8 ANSAM ANSAMBAR V.8 ANSAM with phase reversals V21flag a V21 tone and flags for fax answering V18txp1 a V.18 txp signal played in V.21 channel (1) V18txp2 a V.18 txp signal played in V.21 channel (2) Default may be provisioned CallingSignal SignalID: callsig (0x0003) SignalType CN Parameters callSigname Parameter ID cSn (0x0001) Type Enumeration Possible values: CT V.25 Calling Tone CNG T.30 Calling Default may be provisioned SignalName: V8bisSignal SignalID: v8bs (0x0004) Signaltype BR Parameters V8bisSigname ParameterID V8bsn (0x0001) Type Enumeration Possible values ESi V.8bis signal ESi ESr V.8bis signal ESr MRe V.8bis signal MRe MRd V.8bis signal MRd CRe V.8bis signal CRe CRd V.8bis signal CRd MS V.8 bis message MS with contents in signalvalue CL V.8 bis message CL with contents in signalvalue Bilias, Kallas [Page 45]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 CLR V.8 bis message CLR with contents in signalvalue ACK V.8 bis message ACK with contents in signalvalue NAK V.8 bis message NAK with contents in signalvalue Default may be provisioned V8bisSigContents ParameterID V8bscont (0x0002) Type string Possible values Valid contents for the V.8 bis signals Default is empty Description: Some of the V.8 bis signals are messages. Their contents can be defined with theV8biscont parameter. 16.4 Statistics none 16.5 Procedures The Call Type Discrimination package is invoked for cases when the net- work connection is complete and the call may enter one of the types of voice, fax, text telephone and modem. The package contains functionality to support the decision and connection processes. Once discriminated and the modem handshaking completed, an appropriate specific call type pack- age should be invoked to complete the connection establishment on the modulationlevel and perform the session. If the desired call type is known from the beginning, the call type discrimination package should be invoked in order to actively try to establish a connection by sending out stimulating signals. By contrast this package is also used to pas- sively monitor the line to detect signals which are to be relayed to the Media Gateway Controller as input to a discrimination decision. Since the Call Type Discrimination package can be invoked to initially only monitor the line, it can be invoked on lines where voice calls are the most common mode of operation. There may be situations where this pas- sive way of working results in less efficient or less reliable connec- tion in fax/text/data mode. Operation ---------- The package is added to a termination of a line when an outgoing or incoming call where fax, text or data mode may be wanted. The properties are set to the enabled call types. For incoming calls: The call is answered, the destination is evaluated and the remote call initiated using packages and gateway functions outside the scope of this package. The MGC may order stimulating signals defined in this package Bilias, Kallas [Page 46]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 to be sent on the line. The line is monitored for signals for the selected modes as defined in the dtone" event descriptor. The MGC is expected to evaluate call type indications of all types; registered type of the destination, offered capabilities of the endpoint, invoked con- nection efforts of specific types from the endpoint and discriminating events from a call type discriminating package active in setting up the connection with the other endpoint. As soon as the modem handshaking is complete and a condition is reached that is valid for only one call type, a package for handling that call type should be invoked by the MGC, thus placing the MG into the desired mode of operation. The pack- age contains components for conducting a negotiation procedure according to the different connection procedures defined in recommendations V.25 [16], V.8 [13], V.8 bis [14], T.30 [11], T.38 [12] and V.18 [15]. (V.8 bis support is optional and its availability can be interrogated through the property V8bissupport). Operation for transit calls, coming from and going to the switched network. --------------------------------------------------------------------------- If no fax/text/data indication is present in the incoming call, the out- going call is placed in voice mode, with the Call Type Discrimination package active. If a valid tone is detected, it is reported to the MGC as an event, if there is not enough information for discrimination, it is signalled to be replayed at the other end. The process continues according to the rules of the connection procedures until the call type can be determined and the mode of operation can be established. Operation for calls having one endpoint in the packet network. -------------------------------------------------------------- If no fax/text/data indication is present in the incoming call, the out- going call in the packet network is placed in voice mode. If a request to open a text channel, a fax channel or a data channel is made, the corresponding call type is tried on the switched network connection. If a signal indicating presence of a fax, textphone or a modem is received from the circuit switched network, and the call type can be evaluated, a corresponding channel is requested to the remote endpoint. If that request is acknowledged, the connection in the fax/text/data mode is completed on the switched side. If the call type can not be evaluated, further signal exchange is per- formed on the switched interface until the call type is determined, and then the channel establishment continues on the packet side. Cases when the call type can not be determined from the signals --------------------------------------------------------------- Bilias, Kallas [Page 47]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 For cases when the call type can not be determined by the signal exchange, a decision must be taken by other means, or a transparent transport can be selected. The other means to make the decision may be a number analysis and comparison to registered user preferences or network defaults. Cases when the decision is not possible by signal analysis but need to be taken by external means: V.21 Used both for text telephony and for credit card transactions. The decision is recommended to be based on regional preferences and registering preference for data per destination number in regions where the default preference is for text telephony. V.23 Used both for Minitel-based text telephones and for the Minitel information Retrieval system. The conflict is only when an answer- ing endpoint transmits the v23hi signal. A tranparent data tran- sport is recommended for this case. Scenarios and call flows ------------------------ Signal sequence scenarios can be derived from the different connection protocols, with T.38 being the main protocol for fax, V.18 for text telephony and V.8 / V.25 for data. The typical fax scenario is discriminated when CNG is detected from the calling end and a corresponding CED and V.21flags are detected at the answering end. Alternatively, a V.8 CM or JM signal with a fax call type may be detected at either end. The text telephone scenario is discriminated when a text telephone call type is detected in V.8, a text telephone function is negotiated in V.8 bis, or a signal valid for text only is detected. The data scenario is discriminated when a data call type is detected in V.8, a data function is negotiated in V.8 bis, or a data mode (not text) is entered by any part. In all cases the Call Type discrimination package completes the handshaking protocol before entering the selected data mode. 17 FAX PACKAGE Package Name: Fax PackageID: fax (0x0040) Bilias, Kallas [Page 48]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Version: 1 Extends: None Description: The fax package is intended for enabling real time or store and forward fax communication between terminals/applications in different networks or messaging environments. This package includes the mechanisms needed to transport T.30 fax sessions (signals and data) in a real time IP environment. The transport mechanism will be different for each environment where the package is used. 17.1 Properties Fax connection state PropertyID: faxstate (0x0001) Type: Enumeration Possible values: Idle for no connection efforts Prepare for being known in the termination and ready to accept connections Negotiating for taking the initiative to establish a fax connection Training Fax Phase B training underway Connected for completed connection EOP Procedures Complete ProcInterrupt Procedure Interrupt Processing Characteristics: Read/Write Defined in: Termination State Description: The connection state property is used to request a fax connection, and reflect the state of the achieved fax connection. Parameters Transport ParameterID: trpt (0x0001) Type: Enumeration Possible values: T30 for T.30 PSTN sessions without V.8 T.30V8 for T.30 PSTN sessions with V.8 T38UDPTL for T.38 using UDPTL T38TCP for T.38 using TCP T37 for T.37 RTP for RTP (e.g., G.711) Characteristics: Read/Write Defined in: Termination State Description: Bilias, Kallas [Page 49]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 The Transport parameter reflects the transport mechanism selected for the fax termination. TransmissionSpeed ParameterID: trspd (0x0002) Type: Integer Possible values: 1200-14400 Description: The Transport parameter reflects the transmission speed seen at the analog interface for the fax relay or the transmission speed used by the FAX termination (T.30 PSTN). PSTN Inteface ParameterID: pstnif (0x0003) Type: Enumeration Possible values: NA not applicable V17 V27TER V29 Description: The PSTN Interface parameter reflects the interface used to connect to a physical FAX machine. 17.2 Events Fax Connection State Change Event ID: faxconnchange (0x0001) EventDescriptor Parameters: None ObservedEventDescriptorParameters Fax Connection Change ParameterID: faxconnchng (0x0001) Type: Enumeration Possible Value: EOF - end of fax session, call terminating PI - Priority Interrupt ; Switch to Voice Description: This event will occur when the fax connection state for the termination has changed. Its parameter is the new contents of the Fax Connection State property. 17.3 Signals None 17.4 Statistics Bilias, Kallas [Page 50]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 Pages Transferred StatisticsID: pagestrans (0x0001) Type: integer Description: No of pages of fax image data transferred through the termination. Train Downs StatisticsID: traindowns (0x0002) Units: count Description: Number of ties FAX trained down during transmission. 17.5 Procedures The following are standard transport mechanisms for fax in different environments. * In T.30: Use T.30 procedures without V.8 * In T.30 Annex C/F: Use T.30 procedures selected via V.8 * In T.38 Annex B: UDPTL or TCP in T.125 communication channel environment. * In H.323 Annex D: UDPTL or TCP as selected with H.245 messages. * In T.38 Annex D (SIP):UDPTL or TCP as initiated with SDP * In T.38 Annex E: UDPTL or TCP * In T.37: SMTP (MIME) /TCP Function -------- A termination with Fax provides a method for transfer of fax pages pre- ceded by negotiations in the call setup according to procedures defined for each environment. When matching capabilities exist, the appropriate sessions can be established in order to transfer pages of image or binary data. Real time fax allows telecom users to transfer fax pages in real time. The procedural aspects of GSTN fax are defined in ITU-T T.30. [11]. The compression methods used in transporting fax images are defined in T.4, T.6, T.81, T.82, T.85 and T.44. In traditional T.30 without error correction, images are transferred in a stream one page at a time. In T.30 with error correction, images are transferred in blocks that are also known as partial pages. Numerous examples of fax sessions are con- tained in Appendix IV to T.30. For each transport environment, a suitable transport protocol must be selected to carry the image. Currently defined and Recommended transport environments for T.30 media streams that can be supported by this pack- age are: Bilias, Kallas [Page 51]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 1. GSTN networks, where the procedures are defined in T.30, T.30 Annex A (for error correction), T.30 Annex C (duplex protocol) and Annex F (half duplex V.34 protocol). 2. Packet networks, where the procedures described in T.38 Annex B [12] can be used to for setting up and conducting fax sessions, using TCP or UDPTL for the transport of T.30 signals and data. 3. Packet networks, where the procedures described in H.323 Annex D can be used to for setting up and conducting fax and voice ses- sions, using TCP or UDPTL as negotiated via H.245. 4. Packet networks, where the IETF Session Initiation Protocol SIIP can be used for setting up and conducting fax sessions as defined in T.38 Annex D using UDPTL or TCP for the transport of T.30 sig- nals and data. 5. Packet networks, where H.248 can be used for setting up and con- ducting fax sessions as defined in T.38 Annex E using UDPTL or TCP for the transport of T.30 signals and data. 6. Packet networks, where the packets of G.711 coded data (with T.30 signals and data embedded) can be transported via RTP. 7. The Extended Simple Mail Transport Protocol messaging environment over packet, that can be used alone or in conjunction with any of the environments above, where T.37, RFC 2301-2305 and RFCs 2530- 2532 specify the methods for transporting image/tiff files using the same compression methods as specified for use in T.30. Interworking between these forms of fax can be achieved through the use of gateways with packages defined here. Process of Adding Fax Capable Terminations ------------------------------------------ The MGs are responsible for detecting fax tones and relaying the related events to the MGC. The MGC should conduct Call Discrimination as defined within the Call Type Discrimination Package in order to deter- mine whether a fax or other mode is applicable. The MGC may choose to skip this if the MG is not capable of the Call Type Discrimination Pack- age. Once the MGC evaluates the tones and determines that the incoming call is fax, the MGC shall execute appropriate ADD commands to specify the desired mode of operation. Process of Ending a Fax Call ---------------------------- Bilias, Kallas [Page 52]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 The MGs are responsible for detecting events that would cause the interruption of a fax call. The MGC is responsible for making the determination if this switch can be made and instruct the MGs to switch. It also responsible for switching it back to fax. The MGC should receive indication that the fax call ends from the MG before receiving typical call termination indications. Examples: --------- One possible instruction from an MGC to an MG to modify an existing con- text to a T.38 media stream: MGC to MG: MEGACO/1.0 [123.123.123.4]:55555 Transaction = 14 { Context = 2000 { Modify = RTP/1 { Media { Stream = 1 { Local { v=0 c=IN IP4 124.124.124.222 m=image 1111 udptl t38 a=T38FaxRateManagement:transferredTCF a=T38UdpEC:t38UDPFEC } } } } } } 18 MODEM PACKAGE Package Name: Modem PackageID: mdm (0x0040) Version: 1 Extends: None Description: The modem package is intended for enabling modem termination and modem relay functions when connecting to a PSTN. 18.1 Properties Modem connection state Bilias, Kallas [Page 53]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 PropertyID: modemstate (0x0001) Type: Enumeration Possible values: Idle for no connection efforts Prepare for being known in the termination and ready to accept connections Negotiating for taking the initiative to establish a modem connection Training Modem training underway Connected for completed connection FallFwd Fall Forward - negotiate to high speed FallBwd Fall Backward - negotiate to lower speed Retrain Retrain to new speed ClrDown Terminate connection Characteristics: Read/Only Description: The connection state property is used to request a modem connection, and reflect the state of the achieved modem connection. Parameters: Transport ParameterID: trpt (0x0001) Type: Enumeration Possible values: RTP for RTP (e.g., G.711) Description: The Transport parameter reflects the transport mechanism selected for the modem termination. Currently only G.711 is defined. In the future other codecs will be added. TransmissionSpeed ParameterID: trspd (0x0002) Type: Integer Possible values: 75-56000 Description: The Transport parameter reflects the transmission speed seen at the analog interface for the modem relay or the transmission speed used by the modem termination. PSTN Interface ParameterID: pstnif (0x0003) Type: Enumeration Possible values: V21 V22 Bilias, Kallas [Page 54]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 V22BIS V23 V32 V32BIS V34 V90 K56FLEX Description: The PSTN Interface parameter reflects the modulation used in the session. ReceiveSpeed ParameterID: rxspd (0x0004) Type: Integer Possible values: 75-56000 Description: The Transport parameter reflects the transmission speed seen at the analog interface for the modem relay or the receive speed used by the modem termination. Framing ParameterID: framing (0x0005) Type: Enumeration Possible values: None MNP4 V42 Description: This parameter reflects the reliability protocol used. Compression ParameterID: compress (0x0006) Type: Enumeration Possible values: None MNP5 V42BIS Description: This parameter reflects the compression algorithm used. Encapsulation ParameterID: encap (0x0007) Type: Enumeration Possible values: Raw PPP SLIP Description: This parameter reflects the encapsulation used. Bilias, Kallas [Page 55]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 18.2 Events Modem Connection State Change Event ID: modemconnchange (0x0001) ObservedEventDescriptorParameters Modem Connection Change ParameterID: modemconnchng (0x0001) Type: Enumeration Possible Value: EOM - end of session, call terminating RETRAIN Description: This event will occur when the modem connection state for the termination has changed. Its parameter is the new contents of the Modem Connection State property. 18.3 Signals None 18.4 Statistics Retrains StatisticsID: retrain (0x0001) Units: count Description: No of retrain sequences seen by the termination. Fall Forwards StatisticsID: fallfwd (0x0002) Units: count Description: No of fall forward sequences seen by the termination. Fall Backwards StatisticsID: fallbwd (0x0003) Units: count Description: No of fall backwards sequences seen by the termination. 18.5 Procedures None 19 REFERENCES [1] ITU-T Recommendation E.180/Q.35 Technical characteristics of tones for the telephone service (03/98) Bilias, Kallas [Page 56]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 [2] ITU-T Recommendation E.182 Application of tones and recorded announcements in telephone services (03/98) [3] CCITT Recommendation Q.724 (1988). Telephone User Part Signalling Procedures [4] CCITT Recommendation Q.764 (1988). Signalling System No.7 ISDN User Part Signalling Procedures [5] ITU-T Recommendation Q.115 (06/97) Logic for the control of echo control devices [6] CCITT Recommendations Q.400 to Q.490 (1988), Specifications of Sig- nalling System R2. [7] IETF RFC 1661: Simpson, W., The Point-to-Point Protocol (PPP), July 1994 [8] IETF RFC 1889: Schulzrinne, H., et al, RTP: A Transport Protocol for Real-Time Applications, January 1996 [9] IETF RFC 2138: Rigney, C., et al, Remote Authentication Dial In Service (RADIUS), April 1997 [10] IETF RFC 2661: Townsley, W., et al, Layer Two Tunneling Protocol "L2TP", August 1999 [11] ITU-T Recommendation T.30 (7/96) Procedures for document facsimile transmission in the general switched telephone network. [12] ITU-T Recommendation T.38 (6/98) Procedures for real-time Group 3 facsimile communication over IP networks. [13] ITU-T Recommendation V.8 Procedures for starting sessions of data transmission over the public switched telephone network [14] ITU-T Recommendation V.8 bis Procedures for the identification and selection of common modes of operation between data circuit- termination equipments (DCEs).... [15] ITU-T Recommendation V.18 Operational and interworking requirements for DCES operating in the text telephone mode [16] ITU-T Recommendation V.25 Automatic answering equipment and/or parallel automatic calling equipment on the general switched tele- phone network. [17] ITU-T Recommendation T.140 (1998) - Text conversation protocol for Bilias, Kallas [Page 57]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 multimedia application. With amendment 1999. [18] ITU-T Recommendation H.323 Annex G Text Conversation and Text SET [19] IETF G. Hellstrm, "RTP Payload for Text Conversation", Internet Engineering Task Force, RFC XXX [20] ITU-T Recommendation T.134 Text Chat Application Entity [21] ITU-T Recommendation V.17 (02/91) Recommendation V.17 (02/91) - A 2-wire modem for facsimile applications with rates up to 14 400 bit/s [22] ITU-T Recommendation V.27 ter (11/88) - 4800/2400 bits per second modem standardized for use in the general switched telephone net- work [23] ITU-T Recommendation V.21 (11/88) - 300 bits per second duplex modem standardized for use in the general switched telephone net- work [24] ITU-T Recommendation V.22 (11/88) - 300 bits per second duplex modem standardized for use in the general switched telephone net- work [25] ITU-T Recommendation V.22 bis (11/88) - 300 bits per second duplex modem standardized for use in the general switched telephone net- work [26] ITU-T Recommendation V.23 (11/88) - 600/1200-baud modem standard- ized for use in the general switched telephone network [27] ITU-T Recommendation V.32 (03/93) - A family of 2-wire, duplex modems operating at data signalling rates of up to 9600 bit/s for use on the general switched telephone network and on leased telephone-type circuits [28] ITU-T Recommendation V.32 bis (02/91) - A duplex modem operating at data signalling rates of up to 14 400 bit/s for use on the general switched telephone network and on leased point- to-point 2-wire telephone-type circuit [29] ITU-T Recommendation V.34 (02/91) - A duplex modem operating at data signalling rates of up to 14 400 bit/s for use on the general switched telephone network and on leased point-to-point 2-wire telephone-type circuit Bilias, Kallas [Page 58]
Internet draft Megaco/H.248 Other Pkgs 20 January 2000 [30] ITU-T Recommendation V.90 (09/98) - A digital modem and analogue modem pair for use on the Public Switched Telephone Network (PSTN) at data signalling rates of up to 56 000 bit/s downstream and up to 33 600 bit/s upstream [31] ITU-T Recommendation V.61 (08/96) - A simultaneous voice plus data modem, operating at a voice plus data signalling rate of 4800 bit/s, with optional automatic switching to data-only signalling rates of up to 14 400 bit/s, for use on the General Switched ... [32] ITU-T Recommendation T.37 (6/98) Procedures for the transfer of facsimile data via store and forward on the internet [33] ISO/IEC 10646-1:1993 The Unicode Standard, http://www.unicode.org 20 AUTHOR'S ADDRESSES Mike Kallas Nortel Networks P.O. Box 833805 Richardson, Texas 75083-3805 USA Email: mike.kallas@nortelnetworks.com Zacharias Bilalis Siemens Schertlinstr. 8 81379 Munich Germany Email: zacharias.bilalis@icn.siemens.fi Bilias, Kallas [Page 59]
