Oki OKIOFFICE44 Service Manual page 273

Figure A3.1.8 Interface between R44 Board and NCU Board
CPU
IC2
IOGA
HUP-N
Figure A3.1.9 Interface between R44 Board and OPE (operation unit)
Board Descriptions
IC8
S
Rp
Modem
R
IC2
CML
DP
SR
IOGA
MUTE
PBXE
to OPE
CPU
to OPE
R44
CN4 CN1
TXDOPE
1
RXDOPE
2
PSMODE
3
OPRST-N 4
OPECHK 5
6,7
+5 V
8,9
0 V
13
PCI-N
14
RIINT
15
A - 31
R44
NCU
CN10 CN3
S
A8, B8
A4, B4
A6, B6 R
A3
B3
A2
A1
B1, B2
OH2
A15
RI
A14
OPE (04W)
X'tal
IC1
TXD
RXD
MOS CPU
PSMODE
Internal ROM
IRST
OPECHK
+5 V
GND
Eight LEDs
LEDs
OKIOFFICE 44 Serv. Man., P/N 59276801
Receiving
sensitivity control
Relay driver circuit
Hook-up signal
detection circuit
Ringing signal
detection circuit
KSCAN0
to
KSCAN7
Key switch
matrix
KSENS0
to
KSENS7
DB0
to
DB7
LCD unit
Control signals