| 摘要 |
PURPOSE:To make possible to transfer a main wire that is incoming-responded at one key telephone set to another key telephone set by providing a means that sends out an incoming datum to all of the key telephone sets that the said main set has with the detection of an incoming signal which is sent from the main set through a transfer line and connects the key telephone set that is responded to the incoming datum with the transfer line and acquires the transfer line. CONSTITUTION:In a main set A-1, a central control circuit 4a, when receiving a datum, operates a transfer line acquiring relay Aa for a transfer line Ta and closes the connecting point a1 and acquires the transfer line Ta, and also closes the connecting point between the transfer line Ta of a cross button switch 7a and the call line La of a key telephone set A-2 and sends out a transfer line displaying lamp datum to all of the key telephone sets. Thereby, the tele phone set A-2 is enabled to be in an extension call state with a key telephone set B-2 by the connection of the key telephone set A-2 with the said transfer line Ta. Also, the telephone set control circuit 10a of all of the telephone sets of a key telephone set A0 turns on the lamp of the transfer line Ta with receiv ing the transfer line displaying lamp datum. |
