HOOK SWITCH CIRCUIT OF TELEPHONE

摘要

a DTMF signal generating part which generates the frequency corresponding to the key signal at the telephone key part; a micom which converts and controls switching means; a switching transistor which on/off operates; a bell signal line part in order to receive the bell signal by the switching transistor(Q1); the first switching means which converts the connecting circuit; a piezosound generating part by the switching transistor(Q2); the second switching means which converts the transmitting and receiving circuit part.