12
Twintalker 4810
Twintalker 4810
13.6 Changing Channels
13.7 CTCSS (Continious Tone Coded Squelch System) /
DCS (Digital Coded Squelch)
License free PMR radio's operating on the 446 MHz frequency band, like the Twintalker 4810
PMR, have 8 available radio channels. If there are many PMR users in your neighborhood,
there is a chance that some of these users are operating on the same radio channel.
To prevent that you receive signals from other users, sub-channels have been integrated.
Two PMR radio's will only be able to communicate with each other when they are operating
on the same radio channel and when they have selected exactly the same sub-channel.
There are two kind of sub-channels :
•
Continuous Tone Coded Squelch System (CTCSS)
•
Digital Coded Squelch (DCS)
When using CTCSS, a low frequency tone (between 67 and 250 Hz) will be transmitted along
with the voice signal. There are 38 available tones to choose from. You are free to choose
one of these 38 available tones. Due to filtering, these tones will generally not be audible so
they will not disturb the communication.
DCS is similar to CTCSS, but instead of sending a continuous tone of a selected frequency,
a digital data transmission is added to the radio signal. This Digital Code is transmitted at a
really low rate, around 134 bits per second (the code is 23 bits long). Only the PMR's of the
latest generation will support DCS. There are 83 available DCS codes that can be used.
Since earlier models will only support CTCSS it will be better to use DCS to prevent that other
users will be audible during your PMR conversations.
13.7.1 CTCSS
•
Press the
- button
once, the current channel
number flashes on the display.
•
Press the
- button
or the
- button
to change
the channel.
•
Press the
PTT
- button
to confirm and return to stand-by
mode.
•
Press the
-button
twice :
"CTCSS"
and the current
CTCSS code flashes on the display.
•
Press the
-button
or the
-button
to change to
another code.
•
Press the
PTT
-button
to confirm and return to stand-by
mode.
5
9
6
11
If no button is pressed within 5 seconds during setting, the unit will return
to standby.
5
9
6
11
Summary of Contents for TWINTALKER 4810
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