METHOD OF MATCHING OPERATION MODE OF A MODEM.

摘要

Mode instruction signals by DTMF are transmitted and received between digital terminal equipment connected to both ends of the telephone circuit using multi-frequency DTMF codes for selection used in the telephone circuits, such that operation modes of the two modem devices are automatically brought into agreement with each other. That is, even when the initial operation modes are different between the calling side and the called side, a desired operation mode is set on the calling side. After the called side is off-hooked in response to the calling signal, (1) the operation mode instruction signal is sent from the calling side to the called side using DTMF codes, and when this mode can be set on the called side, this mode is set and a response sound is returned back to the calling side. @(35pp Dwg.No.1,3/13)@.