| 摘要 |
<p>KEY TELEPHONE SYSTEM SIGNALLING AND CONTROL ARRANGEMENT A key telephone system having a plurality of telephone station sets for selective connection to a plurality of telephone lines. At least one set having circuitry for transmitting in a selected time slot on a control line, a signal requesting a hold state on the telephone line connected to the set. The system includes a control unit which upon detecting the signal requesting the hold state places a hold network on the telephone line and continues to transmit the signal in the selected time slot. Each of the telephone sets includes circuitry which is responsive to the signal in the selected time slot for indicating the hold status of the telephone line.</p> |
