| 摘要 |
PURPOSE:To make a connection with an optional circuit even during incoming ringing operation by operating buttons by equipping a selecting circuit which selects the output signal of an incoming detecting circuit or a selected button detecting circuit. CONSTITUTION:An incoming signal to a telephone set is detected by an incoming signal detecting circuit 3 and set to the 2nd selecting circuit 5 to select a circuit with top priority. When a hook switch 1 is turned off in said incoming ringing state, an AND signal closes a switching element 6 to form a speech path extending to a telephone set 7. On the other hand, when a circuit selection button 2 for a circuit used for origination is pressed, its signal is sent to the 1st selecting circuit 4, which holds this signal for a certain time. When the hook switch 1 is turned off during said holding operation, a switching element 6 which corresponds to the circuit button pressed previously is closed to form a speech path which corresponds to the circuit and extends to the telephone set 7. |
