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CTCSS/DCS signals from MCU are sent to TCXO for modulation respectively .
CTCSS/DCS signals from receiver are sent to MCU(pin 25) for decoding, and then MCU test if there
are CTCSS/DCS signals with the same setting of the station to decide whether open the speaker or
not.
CTCSS (continuous tone control squelch system, hereinafter referred to as CTCSS), is a kind of
squelch control system with modulation on carrier and continuous sub-audio signals as pilot tone. If
CTCSS function is set, the call is available only at the same CTCSS frequency of both receiving and
transmitting parties to avoid the disturbance of other signals.
The station has 39 groups of standard CTCSS frequency for your selection, such as Table 1.
CTCSS signals produced by MCU are sent to TCXO for modulation.
Table 1
CTCSS Frequency Table
No.
Frequency
[Hz]
1
67.0
2
69.3
3
71.9
4
74.4
5
77.0
6
79.7
7
82.5
8
85.4
9
88.5
10
91.5
DCS signaling：
DCS (Digital code squelch), is a kind of continuous digital code modulated on carrier with voice signal
and used for squelch control. If DCS function is set, the speaker is available only when receiving the
same DCS code to avoid the disturbance of useless signals.
The station has 83 kinds of standard codes including positive and inverse code for your selection, such
as Table 2.
DCS signals produced by MCU (PWM waveform) are sent to TCXO for modulation.
CTCSS/DCS signals from receiver are sent to MCU for decoding, and then MCU test if there are DCS
codes with the same setting of the station to decide whether open the speaker or not.
Table 2
DCS Coding Schedule
023
025
026
031
No.
Frequency
[Hz]
11
94.8
12
97.4
13
100.0
14
103.5
15
107.2
16
110.9
17
114.8
18
118.8
19
123.0
20
127.3
114
174
115
205
116
223
125
226
BR200D-U1/BR300D-U1 Service Manual
No.
Frequency
[Hz]
21
131.8
22
136.5
23
141.3
24
146.2
25
151.4
26
156.7
27
162.2
28
167.9
29
173.8
30
179.9
315
331
343
346
30
No.
Frequency
[Hz]
31
186.2
32
192.8
33
203.5
34
210.7
35
218.1
36
225.7
37
233.6
38
241.8
39
250.3
445
631
464
632
465
654
466
662
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