Icom IC-F2721/D Service Manual

4 - 7
4-6-2 FRONT CPU (FRONT UNIT; IC3)
Pin
number
Port
name
Description
7 RES Input port for rest signal.
19–22
KR0–
KR3
Input ports for the 10-keypad.
(IC-F2800 series only)
28, 29
LIGT1,
LIGT2
Output control signals for LCD back-
light.
47 LEDT Outputs control signal for the TX LED.
48 LEDR Outputs control signal for the RX LED.
51, 52
DICK,
DIUP
Input ports for control signal from the
dial (S9). (IC-F2700 series only)
53, 54
KYUP,
KYDN
Input ports for control signal from [ ],
[ ] keys. (IC-F2800 series only)
57 HANG
Input port for the microphone hanger
detection signal.
Low: While microphone on the
hanger.
58 PTT
Input port for the PTT switch of the
connected microphone.
59–63
KYP0–
KYP4
Input ports for the programmable
function keys (P0–P4).
4-6-4 D/A CONVERTER (MAIN UNIT; IC30)
Pin
number
Port
name
Description
1T1
Outputs the bandpass filters (D23,
D26, D68, D69) tuning signal.
2T2
• While receiving
Outputs the bandpass filters (D17,
D18) tuning signal.
• While transmitting
Outputs the TX power control signal
which selects TX output power of
HIGH, LOW1 or LOW2. The output
signal is applied to the APC amplifi er
(IC37, pin 1).
3 TXLVA Outputs TX VCO lock voltage.
4 RXLVA Outputs RX VCO lock voltage.
4-6-3 D/A CONVERTER (MAIN UNIT; IC8)
Pin
number
Port
name
Description
2 SQL
Outputs AF signal to the squelch cir-
cuit (IC12, pin 8).
3 MOD
Outputs modulation signals to the
VCO circuit.
10 TENC Outputs CTCSS/DTCS signals.
11 BAL
Outputs deviation balance control sig-
nal.
14 BEPV
Outputs beep audio signals to the
speaker via the AF amplifiers (IC34,
IC38).
15 SIGNAL
Outputs AF signals to the speaker via
the AF amplifi ers (IC34, IC38).
22 TONE Outputs single tone signal.
23 REF
Outputs reference oscillator (X2) con-
trol signal.
LIGT1 LIGT2 LIGHT
HIGH HIGH DIM
HIGH LOW OFF
LOW HIGH ON
LOW LOW OFF

Icom IC-F2721/D Specifications

General

Brand	Icom
Model	IC-F2721/D
Category	Transceiver
Language	English