Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Problem with blocked fxs on Cisco 1750

I have network in star topology. Central office - 3640 with fxs , branch offices -1750 with fxs. Links are relised on frame-relay. Sometimes it happens that fxs is blocked ( only on 1750)- if I pick up the phone, there is no signal ( port status is off hook).If someone wants to call to this branch, he will hear busy signal. It doesnt happen on 3640. What should I do to improve this situation. Version of IOS on 1750 - 12.1(5).


Re: Problem with blocked fxs on Cisco 1750

I would recommend you upgrade to 12.2 release and log the error message if problem persists and there's any.

New Member

Re: Problem with blocked fxs on Cisco 1750

If you pick up the phone connected to FXS and you do not receive dialtone, then this could be a hardware problem. Turn on 'debug voip ccapi inout' on the router, and make sure no other calls are in progress, and pick up the phone connected to FXS of 1750 and watch debugs. Do you see "ccGenerateTone" on the debugs? That means we are giving dialtone.

When the port is on-hook does the status indicate onhook (show voice port [port#]). You should have no configuration of commands under voice-port to receive dialtone. If you have PLAR or TRUNK the test above will not be valid ofcourse. If you have either of those, you need to remove them, do FXS troubleshooting and then apply PLAR and/or TRUNK if necessary.

Hope this helps.