Alcatel Carrier Internetworking Solutions Switch/Router 사용자 설명서

Page 28-11

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.

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.