Advantech PCI-1602UP, User Manual

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PCI/ PCI Express-Communication
User Manual 50
5.2 Wiring
5.2.1 5.2.1 RS-232 Signal Wiring
Since the RS-232 interface is not strictly defined, many devices have their own con-
nection methods which may ignore some signal lines or define reserved lines for
other functions. It is best to refer to the user’s 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 PC’s, terminals and some printers. DCE refers to
the device being communicated with or controlled. 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 TXD, a sig-
nal ground and a handshaking line. Examples are printer or plotter connections, trou-
bleshooting and situations where you require only one-wire communication.
Table 5.18: Terminal or PC (DTE) Connections
DB-25 Male DB-25 Male or Female: Terminal
Pin Signal Pin Signal
2 TxD 3 RxD
3 RxD 2 TxD
4 RTS 5 CTS
5 CTS 4 RTS
6 DSR 20 DTR
7 GND 7 GND
20 DTR 6 DSR
8 DCD 8 DCD
Table 5.19: Modem Connections
DB-25 Male Modem (DCE)
Pin Signal Pin Signal
2 TxD 3 RxD
3 RxD 2 TxD
4 RTS 5 CTS
5 CTS 4 RTS
6 DSR 20 DTR
7 GND 7 GND
20 DTR 6 DSR
8 DCD 8 DCD