XR-4200R, XR-4300R, XR-4300RX - Sony Car Audio Service Manual (repair manual). Page 25

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Pin No.

Pin Name

I/O

Description

1

TU-ON

O

Tuner system power supply on/off control signal output to the BA4908 (IC671)
“H”: tuner power on

2

ANT CUT

O

Tuner system power supply on/off control signal output terminal    “H”: tuner power on
Not used (open)

3

BUS-ON

O

Bus on/off control signal output terminal    “L”: bus on    Not used (fixed at “H” in this set)

4 to 6

NCO

O

Not used (open)

7

ILL-ON

O

Power on/off control signal output of the illumination LED and liquid crystal display driver 
(IC901)    “H”: power on

8

VCC

—

Power supply terminal (+5V)

9

E2P SIO

I/O

Two-way data bus with the FM/AM tuner unit (TU1)

10

E2P CKO

I/O

Two-way data bus with the FM/AM tuner unit (TU1)

11

SYSRST

O

Reset signal output terminal    “L”: reset    Not used (fixed at “H” in this set)

12

DOORSW

I

Front panel open/close detection signal input    “L” is input when the front panel is closed

13

LCD SO

O

Serial data output to the liquid crystal display driver (IC901)

14

LCD CKO

O

Serial data transfer clock signal output to the liquid crystal display driver (IC901)

15

LCD CE

O

Chip enable signal output to the liquid crystal display driver (IC901)    “H” active

16

BEEP

O

Beep sound drive signal output terminal

17

UNISI

I

Serial data input terminal    Not used (fixed at “L” in this set)

18

UNISO

O

Serial data output terminal    Not used (fixed at “L” in this set)

19

UNICKO

O

Serial data transfer clock signal output terminal    Not used (fixed at “L” in this set)

20

UNICKI

I

Serial data transfer clock signal input terminal    Not used (fixed at “L” in this set)

21

CD/MD

I

CD/MD selection signal input terminal    Not used (fixed at “L” in this set)

22

FLASH-W

I

Internal flash memory data write mode detection signal input terminal    “L”: data write mode
Not used (fixed at “H” in this set)

23

NCO

O

Not used (open)

24

SIRCS

I

Sircs remote control signal input form the remote control receiver (IC951)
Used for XR-4300R/4300RX

25 to 28

NCO

O

Not used (open)

29

DOOR-IND

O

LED drive signal output of the door indicator (LED801)    “H”: LED on
“H” is output to turn on LED when front panel is opened

30

IFWIDTH

I

IF band detection signal input terminal    Not used (open)

31

NCO

O

Not used (open)

32

NS MASK

O

Discharge control signal output for the noise detection circuit    “H”: discharge

33

VSS

—

Ground terminal

34

C

—

Connected to coupling capacitor for the power supply

35

AD-ON

O

A/D converter power control signal output terminal
When the KEYACK (pin uh) that controls reference voltage power for key A/D conversion input 
is active, “L” is output from this terminal to enable the input

36

RE-IN0

I

37

RE-IN1

I

38

DVCC

—

Power supply terminal (+5V) (for D/A converter)

39

DVSS

—

Ground terminal (for D/A converter)

40, 41

NCO

O

Not used (open)

42

AVCC

—

Power supply terminal (+5V) (for A/D converter)

43

AVRH

I

Reference voltage (+5V) input terminal (for A/D converter)

44

AVRL

I

Reference voltage (0V) input terminal (for A/D converter)

45

AVSS

—

Ground terminal (for A/D converter)

Dial pulse input of the rotary encoder (RE901)
 (for VOLUME/BASS/TREBLE/BALANCE/FADER control)