User busy and fast busy tone

[ariela_81]

I'm using a 2600 router with 12.2(12a) IOS version.

It's receiving calls to terminate them, but it doesn't terminate any. The command "sh call history voice brief" show me all the calls triying to terminate caused by "USER BUSY" and it is giving us a fast busy tone.

Some days ago it didn't had any problems, do you have any idea what can be causing this?

Thanks!

[sbilgi]

You can check in the following document to fing infomation on this:

http://www.cisco.com/warp/public/129/isdn_disc_code.html