Oki 18 Service Manual page 252

RS-232C Serial Interface
(1) Connector
l
Printer side: 25 receptacle
Type: 17LE-13250-27 (D4CC) (made by DDK) or equivalent
l
Cable side: 25-pin plug
Type: 17JE-23250-02 (D8C) (made by DDK)
(2) Cable
l
Cable length: 6 feet (1.8 m) max. (Cable shall be shielded)
Note: Cable is not provided.
3) Interface signal
Pin No. Signal Name
1 Frame Ground
2 Transmitted Data
3 Received Data
4 Request To Send
5 -
6 -
7 Signal Ground
8~17 -
18 +5V
19 -
20 Data Terminal Ready
21~25 -
l
Connector pin arrangement
(4) Signal level
l
MARK polarity: -3V to -15V (LOGIC =1)
l
SPACE polarity: +3V to +15V (LOGIC = 0)
(5) Interface circuit
a) Receiving circuit
Service Guide OKIPAGE 18/18n
Chapter B RS-232C Serial Interface
Signal Compatible
Direction
FG
TD <-- PR
RD --> PR
RTS <-- PR
SG
<-- PR
DTR <-- PR
Nibble
Frame ground
Transmitted data
Received data
Stay space level
(Not connected)
(Not connected)
Signal ground
(Not connected)
+5V (50mA max.)
(Not connected)
Data terminal ready
(Not connected)
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