Telephone answering machine busy signal detection devices with switching means

摘要

A device for use with equipment such as a telephone answering machine whose operation can be controlled by on hook busy signals transmitted to the equipment. Included in the device are switching means which, when actuated, cause transmission of the outgoing signal from the telephone answering machine to be terminated and actuation of a busy signal detector. If an incoming busy signal is present, the detector generates a predetermined output signal which disconnects the telephone answering machine from the phone lines. The switching means may be actuated by sensing means which detect when the amplitude of the outgoing signal falls to a value below a predetermined level and stays at that value for a short time, within a continuing outgoing signal, or for a long time at the end of an outgoing signal. Alternatively, the switching means may be actuated periodically during transmission of an outgoing signal.