Kenwood pds20-18 Service Manual page 17

BLOCK DIAGRAM
CPU UNIT (X77-2110-00)
CONTROL UNIT
(X77-2120-0x)
Rotary Encoder Panel Switch
S11 S1~S10
ROM
IC20 X66-1600-00
Interruption
Input Port
Processing
IC9,14
IC21,22
CPU
IC1,2,4,5,7,13
OUTPUT:LED
Latch Circuit
IC6,8,12
OUTPUT PORT
LED
RAM
Switch
IC15
LED
Display
Drive
IC1,2
X77-2110-00
Option Board
X72-1380-00
X72-1380-01
X72-1460-00