| 摘要 |
PURPOSE:To store a data to a memory regardless of the state of a telephone terminal device to be called by controlling the device that a data is stored from a calling telephone terminal set to a memory circuit of the telephone terminal set to be called via a control channel. CONSTITUTION:A private branch of exchange 1 sets a transmission time slot and a reception time slot assigned to an input/output device 10 of a calling telephone terminal device 30 according to the transmission control block into a multiplex channel, writes information representing to which channel it is assigned into a reception control block assigned semi-fixedly respectively to a calling telephone terminal set 30 and a telephone terminal set 31 to be called and transmits it to the calling telephone set terminal set 30 and the telephone terminal set 31 to be called. When either handset of both the telephone terminal sets 30, 31 is hooked on, a control circuit 7 of the telephone terminal set recognizes it via an input/ output circuit 6, rewrites its transmission control block and requests the disconnection of the set channel to the private branch of exchange 1. |
