| 摘要 |
PURPOSE: To execute a telephone response system and an automatic switch function without using any line for additional electric connection or the other function. CONSTITUTION: A telephone terminal is connected to one telephone line including telephone interface circuits 6, 7 and 8, the respective interface circuits are energized by the ring back tone signal of line and arranged between a telephone line 3 and any one of telephone terminals 13, 14, 15 and 16 and its ring back tone is disconnected from the line. The interface circuit is respectively provided with a circuit for counting the ring back tone and picking up the line and this circuit receives the ring back tone signals appearing on lines L1-L2, counts the predetermined number of ring back tones and picks up the line through a relay when the final ring back tone signal stops. Power is supplied to the system only by the signal on the telephone line. |
