AT&T Communications
AT&T Government Systems
AT&T International
Bell Atlantic
Bell Canada
Bell Communications Research
Bell Northern Research (Canada)
GTE Supply
ITT
International TeleService
Landis & Gyr - Switzerland
Landis & Gyr - North America
MCI Communications, Inc.
MOSCOM, Inc.
NewTel
Northern Telecom
Pacific Bell
Pacific Coin Communications, Inc.
Puerto Rico Telephone Company
Southern New England Telephone Company
Stentor
Teleport Communications, Inc.
Teleport Communications, Group, Inc.
Time Warner Communications
Technology Service Group
Televerket (Sweden)
United Telecommunications
US Sprint
WorldCom