User's Guide

Table Of Contents
Advanced Features
English
120
Using the Smart PTT Feature (Conventional Only)
Smart PTT is a per-personality, programmable feature used in
conventional radio systems to keep radio users from talking
over other radio conversations.
When smart PTT is enabled in your radio, you cannot transmit
on an active channel.
If you try to transmit on an active smart-PTT channel, you hear
an alert tone, and the transmission is inhibited. The LED lights
up solid yellow to indicate that the channel is busy.
Three variations of smart PTT are available:
Mode Description
Transmit Inhibit
on Busy Channel
with Carrier
You cannot transmit if any traffic is
detected on the channel.
Transmit Inhibit
on Busy Channel
with Wrong
Squelch Code
You cannot transmit on an active
channel with a squelch code or
(if secure-equipped) encryption key
other than your own. If the PL code is
the same as yours, the transmission is
not prevented.
Quick-Key
Override
This feature can work in conjunction
with either of the two above variations.
You can override the transmit-inhibit
state by quick-keying the radio. In other
words, two PTT button presses within
the preprogrammed time limit.
APX_4000_M3.book Page 120 Thursday, March 13, 2014 10:59 AM