Busy arrival sound transmission circuit of cordless key telephone system

摘要

PURPOSE: To send a busy state incoming tone to a cordless telephone set only in a cordless key telephone system and to send no tone to a line wire. CONSTITUTION: A master set 1 is provided with a state identification memory 142 of connectors 21-21m, the connectors 21-2m are provided with a sound source 202 for a busy state incoming tone and a switch 262 connecting the sound source 202 to a transmission section 204, and when any incoming call comes to any of line wires 41-4p, the master set 1 references the state identification memory 142 to discriminate whether or not the connectors 21-21m are all busy, and when they are all busy and a busy incoming tone transmission command signal is sent to the connectors 21-21m, and the connectors 21-21m receiving the signal close the switch 262 to apply the busy state incoming call tone outputted from the sound source 202 to the transmission section 204. Since the busy state incoming tone is applied to a transmission speech path (path interposed to the transmission section 204) forming a 4-wire speech path and the relevant incoming call tone is not sent to the line wire and a subscriber using the line wire is not troubled by an undesired signal tone.