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PCI-1625U User Manual 42
5.2 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 for other functions. It is best to refer to the user manual of
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 con-
trolled. Examples include modems, DSU’s (digital service units), printers
and lab/factory equipment. In some situations, you may be able to get by
with just three lines: data on RxD, TxD and ground.
Table 5.5: Terminal or PC (DTE) Connections
DB25 Male DB25 Male or Female: Terminal
Pin Signal Pin Signal
2 TxD 3 RxD
3 RxD 2 TxD
4 RTS 5 CTS
5 CTS 4 RTS
6DSR 20 DTR
7 GND 7 GND
20 DTR 6 DSR
8 DCD 8 DCD