| 摘要 |
PURPOSE:To inform a call request from a waiting subscriber to a subscriber of call waiting service, by receiving a call request signal from the waiting subscriber of a call waiting service system. CONSTITUTION:When an incoming call from one subscriber SUBC is arrived when other subscriber of a call waiting service system CWSUB making a call with a subscriber SUBB, then a call waiting equipment CWE changes over the subscriber into the subscriber SUBC with a relay contact cha by means of hooking, and makes the subscriber SUBB waiting. When the hooking is done again, the subscriber is changed over to the SUBB with the contact cha and the subscriber SUBC is made in waiting state. When the waiting subscriber transmits a call request signal with a PB signal, it is received at a call request signal receiver REC, a relay EMC is operated, a call request indicating tone OSC is induced from the ternary winding of a relay A and transmitted to the CWSUB subscriber. |
