Automatic telephone exchange system for both speech signals and data transfer

摘要

Telephones are coupled with data terminal equipments through data lines. The data lines are used to transfer the terminal data between the data terminal equipments and the telephones. Speech signals are transferred between the telephones and a PCM telephone exchange through speech lines. Control lines are used for transferring a time-division-multiplexed signal made of telephone control signals such as lamp energizing signals, and the terminal data, and also used for transferring another time-division-multiplexed signal made of function signals such as function key actuation signals and the terminal data. With such a connection, a speech signal is transferred between telephones through the PCM telephone exchange and speech lines and the terminal data are transferred through the control lines and the PCM telephone exchange.