Methods and apparatus are provided for handling a STUCK-ON microphone
push-to-talk (PTT) switch. The apparatus comprises an input device
receiving the PTT output, switches for selecting a radio, and a
controller that receives this information and determines whether the PTT
switch is STUCK-ON. Until STUCK-ON occurs, the controller passes the
microphone signal and a PTT initiated TRANSCVER-ON command to the radio
causing it to transmit. When STUCK-ON occurs, the state of the PTT switch
is ignored and the transmitter shut off. The status of other PTT switches
and radios are not affected. In the method, the active PTT signal results
in a TRASNCVR-ON command to the transmitter until a PTT-ON timer reaches
a predetermined critical value Tc, whereupon the PTT-ON signal is
blocked, the transmitter returned to stand-by and an alarm turned on to
warn the pilot of the stuck PTT switch.