ベルシステム
Bell Communications Research, Inc.(英語版) - 全ベビーベルで共有
BellSouth Corporation Southern Bell Telephone and Telegraph Company South Central Bell Telephone Company
Cincinnati Bell, Inc.(英語版) Cincinnati Bell Telephone Company
NYNEX Corporation New York Telephone Company New England Telephone and Telegraph Company
Pacific Telesis Group Pacific Bell Telephone Company Nevada Bell Telephone Company
Southwestern Bell Corporation Southwestern Bell Telephone Company
The Southern New England Telephone Company(英語版)
US WEST, Inc.(英語版) Northwestern Bell Telephone Company Pacific Northwest Bell Telephone Company The Mountain States Telephone and Telegraph Company Malheur Home Telephone Company