Serial Connection

[sawquecisco]

Hi

I have a confusion about naming serial connection.

Router ---------------------> CSU/DSU ---------------------------------> WAN

Which one is "serial" connection? Between Router and CSU/DSU or between CSU/DSU and WAN?

[JohnTylerPearce]

The serial connection will be on the router.

Usually, if you have a T1 circuit from a service provider, it will go into a CSU/DSU device (sometimes included on a router or an additional CSU/DSU device you can installted on the router), into the router. The serial port connecting to the CSU/DSU would be considered the serial connection. Like I said before, some routers will include a CSU/DSU within the router.

[sawquecisco]

Thank you,

So what is the name of connection between WAN and CSU/DSU? or WAN and Modem? Isn't it serial? If it is serial too, is there a difference between router CSU/DSU connection?

[JohnTylerPearce · Accepted solution]

Basically, what it's doing is, converting the carrier signal from the service provider, to a signal that the router/switch can interpret.

[Richard Burts · Accepted solution]

It seems to me that the router to CSU/DSU and CSU/DSU to WAN are both constituent parts of the same serial connection. You need both parts for the serial connection to work (unless you consider the situation where the CSU/DSU is integrated into the serial card in the router). And therefore I believe that the same name applies to both.

HTH

Rick

[Reza Sharifi · Accepted solution]

The name of the cable that connects the CSU/DSU to the router is called V.35. One side of the V.35 is DTE that connects to the router and has 60 pins male.  The other side of the connection is DCE which is female that connects to the CSU/DSU  Out to the provider is usually copper (the last mile or extended dmark).

HTH