User's Guide

Glossary
English
138
Preprogrammed
Refers to a software feature that has been
activated by a qualified radio technician.
Private
(Conversation)
Call
A feature that lets you have a private
conversation with another radio user in the
talkgroup.
Private Line
(PL)
A sub-audible tone that is transmitted such
that only receivers decoding the tone
receives it.
Programmable
Refers to a radio control that can have a
radio feature assigned to it.
PTT
Push-To-Talk – the PTT button engages
the transmitter and puts the radio in
transmit (send) operation when pressed.
Radio
Frequency (RF)
The part of the general frequency spectrum
between the audio and infrared light
regions (about 10 kHz to 10,000,000 MHz).
Repeater
A conventional radio feature, where you
talk through a receive/transmit facility that
re-transmits received signals, in order to
improve communications range and
coverage.
Term Definition
Selective Call
A feature that allows you to call a select
individual, intended to provide privacy and
to eliminate the annoyance of having to
listen to conversations of no interest to you.
Selective Switch
Any digital P25 traffic having the correct
Network Access Code and the correct
talkgroup.
Squelch
Special electronic circuitry, added to the
receiver of a radio, that reduces, or cuts off,
unwanted signals before they are heard in
the speaker.
SSI Synchronous Serial Interface
Standby
An operating condition whereby the radio’s
speaker is muted but still continues to
receive data.
Status Calls
Pre-defined text messages that allow the
user to send a conditional message without
talking.
Tactical/
Non-Revert
The user talks on the channel that was
selected before the radio entered the
emergency state.
Talkaround
Bypass a repeater and talk directly to
another unit for easy local unit-to-unit
communications.
Term Definition
APX_4000_M3.book Page 138 Thursday, March 13, 2014 10:59 AM