Icom IC-T7A Service Manual

4-6
PORT
ALLOCATIONS
CPU
(LOGIC
UNIT)
Pin
number
Port
name
Description
2
REMOTE
Input
port for
remote control signals
from an
optional HM-75A
microphone
via the [EXT MIC]
jack.
3
SD
Input
port for
detected S-meter
signals from
the IC101
(pin
12)
on
the
2F unit.
4
CTCIN
Input
port for received CTCSS
tone
signals.
5
PCON
Output port
for
+3C
regulator circuit
control signals.
HIGH”:
Power ON
6
PLST
Outputs
PLL strobe
signals.
7
PLCK/ECK
Output port
for clock
signals to PLL
and
EEPROM ICs.
8
UL7PDA
DATA
bus line
for PLL.
•
Outputs PLL
DATA when PLL is
locked.
•
When PLL
is unlocked, PLL
IC
releases the port
being pulled up,
therefore, the
CPU receives
“HIGH”
level signal.
9
CTCSS
Output
port for CTCSS
tone signals.
10
DTMF
Output port for:
•
Beep audio
signals while receiving.
•
DTMF
signals or 1750 Hz tone
signal while
transmitting.
(according to versions)
12
NOISE
Inputs
pulse signals for
noise
squelch from the
IC1 01 on the 1
F
unit.
17
LOCK
Input
port for the
[LOCK] switch.
“LOW”: [LOCK]
switch is ON.
21
DIUD
Inputs up/down
signals from the
[DIAL]
control.
22
DICK
Input
port for dial clock
signals.
23
POWER
Input port for the
[POWER] switch.
“LOW”: [POWER]
switch is
pushed.
24
CONT
Outputs LCD
contrast control
signals.
28-31 KR3-KR0
Input
ports for key matrix.
32
PTT
Input
port for the PTT
control circuit.
“HIGH”: When
transmitting.
Pin
number
Port
name
Description
33
RESET
Input port for
reset circuit
(LOGIC unit
IC3).
39
CFC
Outputs
control signals to the
power
supply
of the CTCSS
bandpass
filter
(LOGIC unit
Q45).
“LOW” :
Activates the BPF.
40
ESIO
DATA
bus line for the
EEPROM
(LOGIC
unit IC15) data
signals.
41
BLED
Outputs
[BUSY] LED
control
signals.
“HIGH” : The LED
lights.
42 LIGHT
Outputs
LCD backlight
control signals.
“HIGH” :
The backlight
lights.
43 Mice
Output
port for the
microphone
amplifier
(2F unit IC12).
“LOW” :
Activates
the mic. amp.
44
MM/RM
Outputs a
mute signal.
[MM]
:
Microphone mute
for DTMF or
1750 Hz tone
while
transmitting.
[RM]
:
Audio mute
for squelch
circuit
while receiving.
“HIGH”
: To
mute one of
above.
46 TXSEL
Outputs
transmit frequency
band
control
signals.
“HIGH”
:UHFband
“LOW”
:VHFband
47
HVCO
Output
port for the UHF band
VCO
(DUAL-VCO board
0301 , 0302)
control
signals.
“HIGH” :
Activates the UHF-VCO.
48
LVCO
Output port for the VHF
band VCO
(DUAL-VCO
board
0304,
0305)
control
signals.
“HIGH” :
Activates the VHF-VCO.
49 SHIFT
Output port for
SHIFT signals to
the
shift switches (1 F
unit
0354,
0854).
“HIGH” : Transmit
on VHF
“LOW” :
Transmit on UHF
55
AFON
Outputs control
signals to the AF
regulator circuit (2F unit 0151, 0152).
“HIGH” : Activates
the AF amplifier.
56
H/L
Output
port for the TX output
power
(High or
Low) select signals.
“LOW” : High power is
selected.

Icom IC-T7A Specifications

General

Brand	Icom
Model	IC-T7A
Category	Transceiver
Language	English