Chapter 3: Communications; Cable Pinout; Serial Port Configuration - Microcom 470 Operator's Manual

The 470 is very versatile. It can be interfaced to PC's, mini-computers, main frames, and
special purpose machines. It is capable of serial RS-232-C, Centronics® parallel, and
optionally RS-422/485 serial communication. The following sections explain the communication
interfaces.
Out of the box, unless otherwise requested, the Microcom 470 communicates using serial RS-
232-C at 9600 baud, 8 data bits, 1 stop bit and no parity with both hardware and software
handshaking. This configuration may be changed as shown in Appendix E.
3.1

CABLE PINOUT

Table 1 shows the signals of the 470's 25-pin RS-232 serial port and table 2 shows the parallel
port configuration.
If serial RS-232-C communication is selected and XON/XOFF hand shaking is used, the only
signals the 470 requires are the RXD, TXD, and GND signals. If hardware (CTS) hand shaking
is used, a CTS signal is provided and an RTS signal is required. XON/XOFF may be disabled
through software dip switch #1 (see chapter 5). The other signals are offered in the event the
host computer requires these signals.
25 TO 9 PIN
State 470
HI 8 DCD---->---- DCD
XX 3 TXD---->---- RXD
XX 2 RXD----<---- TXD
HI 20 DTR---->---- DSR
LO 7 GND—<->--- GND
HI 6 DSR---->---- DTR
DC 4 RTS----<---- CTS
XX 5 CTS---->---- RTS
HI 18 5V
DB-25
DC = Do Not Care
XX = Indeterminate
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470 Operators Manual

CHAPTER 3: COMMUNICATIONS

Serial Port Configuration

Direction PC
5
DE-9
State 470
1 XX 3 TXD---->---- RXD
2 XX 2 RXD----<---- TXD
3 HI 20 DTR---->---- DSR 6-8
4 LO 7 GND—<->--- GND
HI 6-8 DSR---->---- DTR 20
6 DC 4 RTS----<---- CTS
7 XX 5 CTS---->---- RTS
8 HI 18 +5V---->---- +5V 18
DB-25
DC = Do Not Care
XX = Indeterminate
Table 1
25 TO 25 PIN
Direction
DB-25
PC
3
2
7
4
5
13