| 摘要 |
PURPOSE:To inform the existence of the hand-free answering function through transmission of the special signals and thus to realize answering suited for the answering function. CONSTITUTION:When the handset of the key telephone set is picked up, extension call current supply circuit NT in main unit EX operates to supply the call current via extension call line TL. At the same time, count development circuit CT is actuated. With dialing circuit CT counts the pulses to then transmit them through the specified terminal. The transmitted (+) potential starts both reception amplifier R-AMP and transmission amplifier T-AMP for hand-free answering use of extension hand-free circuit HF in No.1 telephone TEL incorporating the hand-free answering function. Then the incorporation of circuit HF is detected at hand-free detection control circuit HFK and via the output of amplifier T-AMP. |
