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8.0 User MENU Options via Front Keypad
Below is the Programming Tree as it looks when one accesses
the various enabled (default) user accessible functions. The
List, Sequence, etc. may change depending
on software configurations made by user or
firmware revision level).
Highlight using select button, then rotate the
channel selector or use UP—DOWN key.
8.1 IN ANALOG CHANNEL MODE:
tree as follows
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5.2 About Sub-Audible QT (Quiet Tones)
(CTCSS) and Digital Sub-Audio (DQT / DCS)
Tones
QT or CTCSS (Continuous Tone-Coded Squelch System
is a
circuit found in a two way radio transceiver that is used to reduce
the annoyance of listening to other users on a shared two way
radio system where more than one user group is on the same
channel and frequency, (called
co
-
channel users
). Using CTCSS
or QT filters out other users if they are using a different CTCSS/
Qt tones, or no CTCSS. DQT or DCS is called Digital Coded
Squelch, similar to CTCSS.
Example:
One may have both the Fire Dept. and EMS on the
same frequency. During standard operations, one may not want
to hear the other. The two-way radio receiver's audio turns on
only in the presence of the correct sub audible tone that only the
radio hears that corresponds to the respective agency
’
s pro-
grammed sub-tone. Therefore in this application, Fire uses one
sub- tone, EMS another.
Conventional radios without CTCSS (or
CTCSS turned off, or seeing the User pressing the MONI button
on the K-911 would hear all transmissions from both groups. The
Firefighters would have to listen to the radio traffic from EMS
while EMS would hear all conversations from Fire.
If the radios are programmed with 2 different CTCSS tones on
two different channels using the same frequency, units from
each group would only hear radios from their own Department
that are programmed to the same CTCSS or DCS code number
of their group. Using this also reduces missed messages and the
distraction of unnecessary radio traffic from the other Agency.
There are many other uses for CTCSS/DCS often called PL
TONES (Motorola term) or Channel Guard. (A GE term).
Prior to programming a radio one therefore needs to mark
down the following:
-Receive Frequency
-Receive Tone (If CSQ is written, there is no tone used)
-Transmit Frequency
-Transmit Tone
-Whether the radio is to operate in narrow or wide band
-The channel alias associated with the particular radio
channel
This information should be available from your communications
officer.
