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5 - 5
• CPU (FRONT UNIT; IC1)
Pin
No.
Port
Name
Description
I/O
1−3
KR1−
KR3
Dealer-programmable keys input.
I
10
CCS
Chip-select signal to the attached optional unit. O
19−
21
CENC0−
CENC2
CTCSS/DTCS signal.
O
23
DUSE
Frequency response of tone filter (IC5)
switching control.
“Low”=While transmitting.
O
24
IPTT
PTT input.
“Low”=PTT is pushed.
I
25
HANG
Microphone on/off hook detect.
“Low”=The microphone is off hook.
I
30
PLST
PLL strobe to the PLL IC (MAIN-A/-B UNIT; IC4,
pin 11).
O
34
ULCK
PLL unlock detect signal from the PLL IC
(MAIN-A/-B UNIT; IC4, pin 7).
“Low”=While the PLL circuit is unlocked.
I
35
LED1
Key indicator LED for [P1] (DS9) control.
“High”= Lights.
O
36
LED2
Key indicator LED for [P2] (DS8) control.
“High”= Lights.
O
37
LED3
Key indicator LED for [P3] (DS7) control.
“High”= Lights.
O
28
POSW
[PWR]
key input.
“Low”=Pushed.
I
39
DSDA
Serial data to the D/A converter (MAIN-A/-B
UNIT; IC20, pin 6).
O
43
SENC
DTMF signals to the LPF (IC5, pin 3).
O
44
BEEP
Beep audio.
O
45
SDEC
DTMF signals.
I
46
CDEC
CTCSS/DTCS signals.
I
48
BATV
Power supply voltage.
I
49
LVIN
VCO lock voltage.
I
50
RSSI
Received signal strength level signal from the IF
demodulator IC (MAIN-A/-B UNIT; IC1, pin 12).
I
51
TEMP
Temperature sensing voltage.
I
52
AFVI
[VOL]
dial (R14) input. (divided voltage of “5V”
line)
I
59
RES
CPU reset signal from the reset IC (IC8, pin 1).
“Low”=CPU is reset.
I
69
CSFT
CPU clock shift signal to the clock frequency
shift switch (D6).
O
71
DAST
Strobe signal to the D/A converter (MAIN-A/-B
UNIT; IC18, pin 7).
O
72
IGSW
Ignition SW input.
I
75
NOIS
Noise signal from the IF demodulate IC (MAIN
-A/-B UNIT; IC1, pin 13).
I
82
ESDA
Serial data to the EEPROM (IC3, pin 5).
O
85
ESCL
Clock signal to the EEPROM (IC3, pin 6).
O
86
PWON
Transceiver's power control.
“High”=Power ON.
I
87
CH4L
Channel indicator LED for [CH4] (DS3) control.
“High”= Lights.
O
88
CH3L
Channel indicator LED for [CH3] (DS4) control.
“High”= Lights.
O
89
CH2L
Channel indicator LED for [CH2] (DS5) control.
“High”= Lights.
O
90
CH1L
Channel indicator LED for [CH1] (DS6) control.
“High”= Lights.
O
95
LIGT2
Key backlight LED (DS1, DS2) control.
“High”=Backlight is ON.
O
96
TLED
TX indicator LED (DS10) control.
“High”= Lights red (While transmitting).
O
97
RLED
RX indicator LED (DS10) control.
“High”= Lights green (While receiving).
O
Pin
No.
Port
Name
Description
I/O
98
SCK
Serial clock signal to the PLL IC (IC4, pin 9)
and D/A converters (IC17, pin 3/IC18, pin 8/
IC20, pin 7).
O
99
SO
Serial data to the PLL IC (IC4, pin 9) and D/A
converters (IC17, pin 3/IC18, pin 8/IC20, pin 7).
O
100
KR0
Input ports for dealer-programmable keys.
I
• EXPANDER (MAIN-A/-B UNIT; IC17)
Pin
No.
Line
Name
Description
4
RXC
T8V, R8V lines and RX VCO ON/OFF control.
5
AFON
AF mute SW (Q35) control.
“Low”=Mute
6
NWC
• RX passband width switching signal to the 2nd
IF fi lter SW (D56, D57).
“Low”=Narrow mode
• RX passband width switching signal to the
phase shifter SW (Q5).
“Low”=Wide mode
7
RMUT
AF mute signal to the analog switch (IC3,
pins 12, 13).
“Low”= While the squelch is closed or trans-
mitting.
12
HORNO
External device control.
“Low”= Pin 6 of OPC-1939 or pin 10 of OPC-
2078 (if connected) is “Low.”
13
TMUT
Transmit mute signal to the transmit mute switch
(Q46).
“High”=Transmitting is muted.
• D/A CONVERTER (MAIN-A/-B UNIT; IC18)
Pin
No.
Description
2, 3
MIC signal level adjustment.
4, 5
RX AF/MIC signal level adjustment.
16, 17 Tone signal level adjustment.
18, 19
Oscillation frequency control voltage to the reference
frequency oscillator (X2).
20, 21 Modulation signal level adjustment.
22, 23 Beep sound loudness adjustment.
24, 25 Squelch threshold level adjustment.
• D/A CONVERTER (MAIN UNIT; IC20)
Pin
No.
Line
Name
Description
1
T1
• While receiving
Tuning voltage to the tuned BPF (D4, D8).
• While transmitting
TX power level setting signal to the APC AMP
IC2).
2
T2
Tuning voltage to the tuned BPF (D9, D10).
3
TLVA
Oscillation frequency correcting voltage to the TX
VCO (Q13, D16, D18, D31, D53).
4
RLVA
Oscillation frequency correcting voltage to the RX
VCO (Q14, D33, D34, D52).
5-5 PORT ALLOCATIONS