Alcatel Omni Switch/Router, User Manual

Page: 837 / 1100

Cable Interfaces for Universal Serial Ports
Page 28-11
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.