Service manual

Operating Manual SL6000 Series
Page 16 of 27
Squelch options
The Radio supports 2 kinds of squelch options. A different squelch option can be applied
to each channel. Sub Audible Tone (SAT) codes are made up from frequencies which are
below 300Hz. These frequencies are lower than the voice audio band. The two most
common forms of SAT codes are CTCSS, Continuous Tone Coded Squelch System, and
DCS, Digitally Coded Squelch.
CTCSS/DCS information may be added to speech during transmission. A receiving radio
can then be programmed to behave according to which tones or codes are being sent by a
transmitting radio.
The SL6000 Series radios are capable of generating all 47 standard CTCSS tones and
can also generate the 83 standard DCS codes and 83 inverted DCS codes.
CTCSS
47 kinds of TIA/EIA Standard CTCSS Tones can be set up. All tones can be set up using
PC Programmer.
TX Operation: If PTT key is pressed, the radio transmits programmed CTCSS tone.
RX Operation: If CTCSS Tone is detected, the Radio status is changed from Busy to
Correct Call. If the CTCSS Tone is not detected, the radio would stay in Busy mode or
change from Correct Call to Busy mode.
DCS
The radio supports 83 kinds of TIA/EIA Normal/Inverted DCS codes.
TX Operation: If PTT key is pressed, the Radio transmits pre-programmed DCS Bit
pattern.
RX Operation: If DCS Data Stream is detected, the radio status will change from busy
mode to correct call. If DCS data stream is not detected, the radio will stay in busy mode
or be changed from correct call back to busy mode.
Monitor
Squelch defeat operation
Pressing the monitor key will open the squelch and switch on the loudspeaker. Everything
on the channel, including FM noise, will be heard.
It is possible to disable the monitor key via the programmer, to prevent a user openly
monitoring a channel in a closed user group system.
B
B
B
a
a
a
s
s
s
i
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i
c
c
c
R
R
R
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a
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d
d
d
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o
o
o
O
O
O
p
p
p
e
e
e
r
r
r
a
a
a
t
t
t
i
i
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n
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g
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g