Alcatel Carrier Internetworking Solutions Switch/Router Cable Interfaces for Universal Serial Ports

Cable Interfaces for Universal Serial Ports
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Cable Interfaces for Universal Serial Ports
The WSX automatically senses the cable type that you plug into one of its Universal Serial
Ports. It can sense whether the cable type is DCE or DTE and whether it is one of the
following interfaces:
• RS-232
• RS-449
• RS-530
• V.35
• X.21 (European)
All cable types (except RS-232) are capable of access rates from 9.6 kbps to 2 Mbps. The RS-
232 cable is not compatible with speeds greater than 64 kbps. Each cable type is illustrated
and described in Appendix B, “Custom Cables.”
The WSX port is normally considered a physical DTE device. It is possible to turn it into a
physical DCE device simply by plugging in a DCE cable. The WSX board internally senses
whether a DCE or DTE cable is connected.
DTE/DCE Type and Transmit/Receive Pins
The RS-232 protocol, which is employed at the physical level for all cable types, always
defines Transmit and Receive pins in relation to the DTE. So, the type of cable you attach
(DCE or DTE) determines the direction of data flow on your connector’s Transmit and Receive
pins.
If the WSX port is a physical DTE, which is probably the most common configuration, then
data is received on Receive pins and transmitted on Transmit pins. If you are using a WSX
port as a physical DCE, then data is transmitted on the receive pins and received on the
transmit pins.