Transaction Network, Telephones, and Terminals: Dial Access Interface
K. L. Cohen, R. F. Ricca · Bell System Technical Journal · 1978
The basic purpose of the Transaction Network is to switch messages between remote stations and Customer Service Centers and between CSCs. The access method may be either polled or dial-in. Dial-In Service is included in TN to provide economical access to the message switch for low volume users. This paper describes the Dial-In Access Network which involves three protocols between dial telephones and the message switch.