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2-Tone (LMR) Signalling
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LMR (2-Tone)
PMR (5-Tone)
What is 2
What is 2
What is 2
What is 2----Tone Signalling?
Tone Signalling?
Tone Signalling?
Tone Signalling?
1. Originally called “Quick Call”, this signalling protocol
was developed by Motorola in the 1950’s.
2. 2-Tone (Quick Call) was designed to add Squelch
specificity especially for emergency service radios.
3. LMR consists of two distinct signals sent over the air
to a radio or a group.
4. Each tone can be configured within a 250 Hz and
3300 Hz tone frequency.
5. “Stun/Kill – This function allows the dispatch
console to disable, temporarily or permanently, a unit
using the 2-Tone capabilities. When “Stun” is used,
the unit may regain its functionality by entering a
password. When Kill is used, the radio only regains
functionality by reprogramming the unit using the
cloning software.
6. RX Code Text – Allows the programmer to add an
“Alpha Numeric” text tag to each tone for
identification at decode and encode if the unit has a
display.
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5. Normally, the duration of the tones varies from one
(1) to three (3) seconds in length no space between
the tones. Tone lengths of up to 10 seconds are
commonly seen in existing applications.
6. ICOM radios allow variable tone periods and spaces
(no tone) between the tones.
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2----Tone Features
Tone Features
Tone Features
Tone Features
1. “Selective Calling” – allows the dispatch console to
page an individual unit. It allows 1 (one) encoding
tone set per channel or up to 3 (three) receive tones
in the radio.
2. “Group Calling” - allows the dispatch console to page
a group.
3. “Answer Back Call” – Also known as “Radio Check”
allows the dispatch console or another portable, to
send a tone to a particular radio and when the target
radio receives the tone it answers back with another
tone. This function serves as a tool to verify if a unit
is “ON” and within range.
4. “Auto Transmit” – Also known as “Radio Spy” allows
the dispatcher to send a 2-Tone signal to the radio
causing it to open its transmitter microphone audio
(Hot Mic) in order to listen to whatever is happening
in the proximity of the radio. This is also very useful
in emergency cases where the user may not be able
to trigger the microphone.
display.
7. Variable Signals – This allows the user/programmer
to set the “Beep and Bell” to different formats for
easier identification when a signal is received.
