Terminal apparatus with a handset using a four pin connector

Claim 1

A terminal apparatus comprising: a main body; and a handset assembly including a transmitter, a receiver and a hook switch, said handset assembly being detachably connected to said main body through a modular jack having a predetermined number of pins, said handset assembly further including a bypass element for accommodating a bypass d.c. component therethrough and thereby bypassing said receiver; a capacitor for preventing a split d.c. component from reaching said receiver, said capacitor being connected in parallel with said bypass element and in series with said receiver; said hook switch is connected to one of said pins to which said receiver is also connected; said main body includes a d.c. power supply for supplying a d.c. component to said handset assembly through the pin to which said hook switch is connected and a detector means for detecting a status of said hook switch depending on a status change of said d.c. component, and an integrating circuit for integrating an integrated d.c. component and inputting an integrated signal into said detector means.