Oki OKIOFFICE84 Maintenance Manual page 279

IC8
Modem
IC2
IOGA4
Figure A3.1.7 Interface between R51 Board and NCU Board
R51
IC2
TXDOPE
RXDOPE
PSMODE
IOGA4
OPRST-N
OPECHK
+5 V
0 V
PCI-N
RIINT
HUP-N
Figure A3.1.8 Interface between R51 Board and OPE (operation unit)
R51
CN10 CN3
S A8, B8
RP A4, B4
R A6, B6
CML A3
DP B3
SR A2
MUTE A1
PBXE B1, B2
OH2
A15
to OPE
RI
A14
to OPE
OPE (04W)
CN4 CN1
TXD
1
RXD
2
3 PSMODE
4
IRST
5
OPECHK
6,7
+5 V
8,9
GND
13
14
15
A3 - 9
NCU
S
sensitivity control
R
Relay driver circuit
Hook-up signal
detection circuit
Ringing signal
detection circuit
KSCAN0
to
X'tal
KSCAN7
IC1
MOS CPU
Internal ROM
DB0
to
DB7
Control signals
Eight LEDs
LEDs
Receiving
Key switch
matrix
KSENS0
to
KSENS7
LCD unit
40672201TH Rev. 4
R51