Cables and
Connectors
This Appendix presents technical
information on attaching devices, such as terminals and modems, to the
Communications Server. Included are illustrations of cables and connector
pin assignments.
Contents:
DTE
and DCE Devices
The RS-232-E serial communications protocol
defines two classes of equipment: data terminal equipment (DTE) and
data communications equipment (DCE).
DTE devices include:
- Communications servers
- Terminals
- Serial printers
- Computers with native RS-232-E serial ports
DCE devices include modems and other communications
equipment.
RS-232-E signal assignments are designed for
communications between DTE and DCE devices-a connector pin defined as
an output for a signal from a DTE device is defined as an input for
that signal on a DCE device, and vice versa. Data communication between
the Communications Server and a modem is an example of DTE-to-DCE communications.
Communications
Server Serial Ports
Figure A-1 shows the pin assignments for the
communications server serial ports.
Figure A-1 Communications Server Serial Port Pin Assignments
Note: The 8 pin RJ45 female connector
will also mate with RJ11 and RJ12 male connectors. The RJ11 has
four pins and will connect with pins 3-6 on the RJ45. The RJ12
has six pins and will connect with pins 2-7 on the RJ45.
For software handshaking you can use any RJ
connector. For hardware handshaking you must use an RJ12 or RJ45
connector. For modems using all of the above lines, you must use
an RJ45 connector with 8 pins.
Adaptor
Wiring
The following section describes adaptor wiring
for connecting DTE and DCE devices. When connecting devices, construct
your cables according to the information in the following section, 'Common
RS232 Cables'. In the illustrations, pin assignments for the server
end of the adapter are always shown, and DB-9 and/or DB-25 pin assignments
are shown as examples for the device end of the adaptor.
Common
RS232 Cables
The following section sets out some common wiring
configurations:
Figure A-2 Software Handshaking Cable (3 Wire)
Figure A-3 Hardware Handshaking Cable (Wyse 60)
Figure
A-4 Asynchronous Modem Cable
Figure
A-5 Standard Serial Port to Server Port Inter-machine Cable
Figure A-6 Software
Handshaking Printer Cable
Most printers use Software Handshaking.
This cable should work with most printers.
Figure A-7 Hardware Handshaking Printer Cable
Note: If the terminal or printer does
not use DTR (pin 20) to indicate a busy condition, substitute the correct
signal on the correct pin for DTR (pin 20) on the terminal or printer
end of the cable in the above diagrams.
Some printers also require either or both of
the signals DSR and DCD to be held high to enable the printer to receive
data. This can be achieved by linking DCD and DSR to another signal
on the printer, such as DTR or RTS. Make sure this signal is not
used as the hardware handshaking signal.
Figure A-8 Wyse-60 Attached
Printer Cable
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