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New Member

router serial interface testing

I have cisco 2501 routers but am finding that the serial interfaces are failing. Is ther any way to test the serial interfaces to make sure they work besides trying to connect it to an actual circuit? I know you can do the route to router using a DCE cable but is the any other way to do local test on the interface?


New Member

Re: router serial interface testing

The easiest thing to do is a loopback at the CSU/DSU, assuming you have one. If so, connect the router to the CSU/DSU using the proper cable. Configure the CSU/DSU as you would to connect to a leased line. Do a local loopback at the DSU. If you want to test the CSU/DSU as well, make a loopback plug and insert it in the network interface jack of the CSU (clear the DSU loopback). Either of these methods should bring the serial interface up.