Specifications
18 PCL-741 User's Manual
wiring
RS-232 Signal wiring
Since the RS-232 interface is not strictly defined, many devices have
their own connection methods which may ignore some signal lines or
define reserved lines to other functions. It is best to refer to the users
manual for your device for installation instructions. You may find the
following helpful.
In general, DTE (Data Terminal Equipment) refers to the device that
is leading the communication. Examples include PCs, terminals and
some printers. DCE refers to the device being communicated with or
controlled. Examples include modems, DSUs (digital service units),
printers and lab/factory equipment.
In some situations you may be able to get by with just three lines:
data on TxD, a Signal Ground and a handshaking line. Examples are
printer or plotter connections, troubleshooting and situations where
you require only one-wire communication.
Terminal or PC (DTE) connections
PCL-741 (DTE): DB-9 MALE Terminal (DTE):DB-25
Pin Signal Pin Signal
3 TxD 3 RxD
2 RxD 2 TxD
7 RTS 5 CTS
8 CTS 4 RTS
6 DSR 20 DTR
5 GND 7 GND
4 DTR 6 DSR
1 DCD 8 DCD