serial inteface shows down/down

Question:

>>serial WS-C3560X-48T-L interface up/down

we have private line. serial inteface shows down/down. private line terminates to csu/dsu and than goes to our router. what could be the issue?

serial interface down/down

I checked status yesterday evening and it was showing down/down. what could be the issue? would there be connectivity issue between router and csu/dsu?

Answer:

The link layer is down. Here's a couple of things to check. First replace the cable between the CSU/DSU and the router. Check that the CSU/DSU is functional, try replacing it if you have a spare. Check the smartjack from the carrier and check that there are no red or WS-C3560X-48T-S Price amber lights. Let us know how that goes.

For more WS-C3560X-48T-L news about Price ans Specification, you can click here.

http://www.3anetwork.com/cisco-ws-c3560x-48t-l-price_p46.html