2 rs232 serial communication interface, 1 rs-232 serial cables – Microcom 438 User Manual
Page 18
Chapter 3
Getting Started
438 Operator’s Manual - 880052-0100
3-3
3.2.2
RS232 Serial Communication Interface
The printer provides a 9-pin female D-Sub connector, on the rear panel, for RS-232D serial
communication. The printer is configured as DCE (Data Circuit-terminating Equipment) so a
NULL modem cable is not necessary. A serial data cable is required to use serial
communications, refer to Table 3-1 below for correct cable configurations.
The factory settings, unless otherwise requested, are set at 115200 baud, 8 data bits, 1 stop
bit and no parity with both hardware and software handshaking enabled. The baud rate is
user selectable from 110 to 115,200 and uses software XON/XOFF flow control and/or
hardware CTS handshaking.
If XON/XOFF handshaking is used, the only signals that the printer requires are the RXD,
TXD, and GND signals. If the hardware handshaking is used, then the CTS and RTS signals
are required. The other signals are offered in the event that the host computer would
require them.
3.2.2.1
RS-232 Serial Cables
The printer uses a standard through serial cable, typically referred to as a modem cable,
which may be purchased through Microcom Corporation or a local computer supply
company. A NULL-modem cable is not required because the printer is configured as DCE.
For a 25-pin serial communication port – Use a 25-pin female to 9-pin male cable.
For a 9-pin serial communication port – Use a 9-pin female to 9-pin male cable.
9 to 9 Pin Cable
9 to 25 Pin Cable
State
DE-9
Pin #
Signals /
Directions
PC
DE-9
Pin #
State
DE-9
Pin #
Signals /
Directions
PC
DB-25
Pin #
XX
1
DCD
DCD
1
HI
1
DCD
DCD
8
XX
2
TXD
RXD
2
XX
2
TXD
RXD
3
XX
3
RXD
TXD
3
XX
3
RXD
TXD
2
HI
4
DTR
DSR
4
HI
4
DTR
DSR
20
LO
5
GND
GND
5
LO
5
GND
GND
7
HI
6
DSR
DTR
6
HI
6
DSR
DTR
6
DC
7
RTS
CTS
7
DC
7
RTS
CTS
4
XX
8
CTS
RTS
8
XX
8
CTS
RTS
5
HI
9
+5V
+5V
9
HI
9
+5V
-
DC = DO NOT CARE
XX = INDETERMINATE
Table 3-1
RS-232 Cable Configurations
CAUTION: Connection of a serial port to a parallel port may
result in damage to the printer and/or computer.