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VHF (7610) CIRCUIT DESCRIPTION
5A-6
November 1998
Part No. 001-7600-001
5.4.3 VHF I/O EXPANDER IC5 (MAIN UNIT)
5.4.4 VHF PORT EXPANDER IC11 (MAIN UNIT)
51 BM Outputs control signal for beep mute cir-
cuit Q10. High = Beep muted.
52-
54
CTDA0-
CTDA2
Output port for CTCSS/DTCS signals.
55 HANG Input port for the microphone hanger
detection signal. Low = Microphone on
hook.
90 MTONE Output port for beep audio while receiving
and 2/5 tone signals while transmitting.
91 TONED Outputs DTMF signals.
94-
96
OPV3-
OPV1
Input port for option connector J2 state
(main unit).
97 CTCIN Input port for the CTCSS/DTCS IN
decode signals.
98 SD Input port for S-meter signal.
99 LVIN Input port for PLL lock voltage.
100 TEMP Input port for the transceiver’s internal
temperature.
Pin
No.
Port
Name
Description
2, 3,
10
T1-T3 Output tunable bandpass filter control
signals.
11 T4 Output port for tunable bandpass filter
control signal while receiving and power
control signal while transmitting.
14 REF Output port for reference frequency
control voltage.
Pin
No.
Port
Name
Description
Pin
No.
Port
Name
Description
4 T5C Outputs control signal for T5 and R5 regu-
lator circuits Q27, Q28 (main unit). High =
Transmitting.
5 TMUT Outputs Tx mute switch Q19, Q23 (main
unit) control signal. High = Tx muted.
6 RM Outputs AF mute switch IC4 (main unit)
control signal for the receiver circuit. High
= No receive audio is emitted.
7 MM Outputs MIC mute control signal. High =
DTMF signals are output, etc.
11 HORNO Outputs external device control signal.
High = Matched 2/5-tone signals are
received.
12 AFON Outputs control signal for the AF amplifier
regulator circuit. High = Squelch is open,
etc.
13 AFHPF Outputs AF filter control signal. High =
Filter out CTCSS or DTCS frequency.
14 NWC Outputs receive/transmit passband width
control signal. High = Narrow bandwidth
is selected.