5
047 134 245 365 516 712
051 143 251 371 532 723
054 152 261 411 546 731
065 155 263 412 565 732
071 156 265 413 606 734
072 162 271 423 612 743
073 165 306 431 624 754
074 172 311 432 627
PT6500 SERVICE MANUAL
No. Fr q [Hz] No. Frq [Hz] No. Frq [Hz] No. Frq[Hz]
186.2
1 67.0 11 94.8 21 131.8 31
192.8
2 69.3 12 97.4 22 136.5 32
203.5
3 71.9 13 100.0 23 141.3 33
210.7
4 74.4 14 103.5 24 146.2 34
218.1
5 77.0 15 107.2 25 151.4 35
225.7
6 79.7 16 110.9 26 156.7 36
233.6
7 82.5 17 114.8 27 162.2 37
241.8
8 85.4 18 118.8 28 167.9 38
250.3
9 88.5 19 123.0 29 173.8 39
10 91.5 20 127.3 30 179.9
DCS signaling:
DCS (Digital code squelch) is a kind of continuous digital code
modulated with voice signals on carrier wave to control squelch. If
DCS function is enabled, only in case the same DCS code is
received can the speaker be turned on so as to avoid interference
from useless signals.
83 groups of standard codes (positive and inverse code) are
available. See table 2.
DCS signals generated by MCU (PWM wave shape) pass the low
pass filter to be filtered off the high frequency over 300Hz and then
are sent to VCO and TCXO for modulation. VCO modulates the
high frequency of DCS signals; TCXO modulates the low frequency
of DCS signals.
CTCSS/DCS signals from the receiver are sent to MCU for
modulation. MCU determines whether the DCS encoding of the
receiving signals is identical with that set on the radio and decides
whether to turn on the speaker.
CTCSS/DCS signals generated by MCU (output form pin24 and
pin28, PWM wave), are respectively sent to VCO and TCXO for
modulation.
CTCSS/DCS signals from the receiver are sent to MCU (pin1) for
demodulation. MCU determines whether the signals contain the
same CTCSS/DCS as that set on the radio and decides whether to
turn on the speaker.
CTCSS
CTCSS(continuous tone control squelch system, sub-audio for abbr.)
is a squelch control system modulated on carrier wave with
continuous sub-audio frequency as pilot frequency. If a channel is
set with CTCSS, only when both the CTCSS of the receiver and
that of the transmitter are identical, communication is available,
which avoids interference of other signals.
This radio is equipped with 39 groups of standard sub-audio
frequencies for your selection as shown in
Table 1
CTCSS signals are generated by MCU (PWM waveform) and are
sent to VCO for modulation via upper limiting filter consisting of RC,
which filters high-frequency components over 300Hz.
Table 3.1 CTCSS Frequencies
3.8 Semiconductor Components
MCU Description
Table 3.3 Microprocessor (M30620) Port Description
I/O
O
O
I
O
O
-
-
O
O
I
O
-
I
-
-
I
O
O
O
O
O
O
-
O
O
O
-
O
O
O
-
-
-
O
O
O
O
O
-
I
Port Name
VCCN
TONEO
TONEI
E-SDA
E-SCL
C-BYTE
C-CNVSS
SHIFT
E-TEST
RESET
XOUT
VSS
XIN
VCC
CMMI
INTO
A-RDT
A-TCLK
A-SCLK
A-DI/O
A-TDATA
A-DIR
NC
QT VCO
PLL-LP
PC/TV
NC
QT TCXO
C-TXD1
C-RXD1
C-CLK1
NC
ICA
PABC
APC2 SW
APC1 SW
RX SW
TX SW
C-HOLD
PLL-UL
Function
PLL frequency reference adjustment
2T/5T/DTMF/BEEP signals inout
2T/5 signals input
EEPROM data cable
EEPROM clock cable
Grounding
Grounding
Clock offset H: Clock offset
EEPROM write-protection pin
H: Unwriteable L: Writeable
Reset pin
Clock output pin
Grounding
Clock input pin
Connects to 5V power supply
Grounding
AC dump detecting pin
AK2346 control pin
AK2346 control pin
AK2346 control pin
AK2346 control pin
AK2346 control pin
AK2346 control pin
Blank
CTCSS/DCS output pin (to VCO modulation)
Phase locked loop upper limiting filter switch
H: switching over medium frequency points
Power control or receiver band pass tuning
voltage control
Blank
CTCSS/DCS output pin (to TCXO modulation)
Serial data output, communicates with PC
Serial data input, communicates with PC
Grounding
Blank
Upstage power amplifier power supply control
H: Transmitting
power amplifier control switch
H:transmission
power amplifier control switch L:transmission
Receiver VCO power switch L: Receiving
Transmission VCO power switch L:transmitting
Grounding
Phase locked loop unlocked detection pin
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Table 3.2 DCS Encoding List
023 1 1 4 1 7 4 315 445 631
025 115 2 0 5 331 464 632
026 1 1 6 2 2 3 343 465 654
031 1 2 5 2 2 6 346 466 662
032 1 3 1 2 4 3 351 503 664
043 1 3 2 2 4 4 364 506 703
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