Tait TM9355 User Manual page 101

Transmit timer
Your radio may have a transmit timer that limits the
amount of time you can transmit continuously.
When the transmit timer is about to expire, the
message Transmit timeout imminent appears in the
display, the red LED flashes, and the radio gives three
beeps.
If the transmit timer times out, the call clears down.
Call time limit
In trunked mode, the length of your call may be limited
by the network or by your radio. Your radio may be
programmed to display the time remaining for
your call.
Operating in trunked mode 101