VeriSign Inc This document describes the development and basis of International Telephone Numbering as it has been manifested through the activities and formal instruments of the International Consultative Committee for Telephony (CCIF) and forums of the International Telecommunication Union (ITU). The current practices for International Telephony Numbering are currently contained in a more general instrument, the International Public Telecommunication Numbering Plan, ITU-T Recommendation E.164 (05/97).