This Recommendation sets out the general principles and conditions for the charging and accounting of international conference calls. A conference call is one in which three or more different individual customer locations are connected through a bridging device, allowing all call participants to hear and/or address the others.
ITU-T D.178 Monthly Accounts for Semi-Automatic Telephone Calls (Ordinary and Urgent Calls with or without Special Facilities) - Charging and Accounting in International Telecommunication Services - Drawing up and Exchange of International Telephone and Telex Account*, 1993-01-01 Update