| 摘要 |
PURPOSE:To call a slave set from a master set without affecting on line wire speech by using a user packet channel between the master set and the slave set when the master set calls the slave set while the slave set is holding speech on a line wire. CONSTITUTION:A protocol controller 5 which transmits an interruption control signal to call the slave set 2 by using the user packet channel used arbitrarily is provided at a master set 1 side separately from a communication channel 5a being used in the speech. Also, a protocol controller 5 which transmits a confirmation control signal to transmit the reception of the interruption control signal from the master set 1 to the master set 1 by using the user packet channel 5b is provided at a slave set 2 side. In other words, since the control signal can be transferred between the master set 1 and the slave set 2 by using the user packet channel 5b, the line wire speech can be prevented from being affected. |
