Gateway Problem

[ahmedmid]

Hi guys,

I have a problem with one of my gateways.
It is a strange problem appeared recently and I hope if any one face this problem to tell me how he solve it.
The problem in steps like this :
1- The customer call the gateway from an external number.
2- He hear a dial tone.
3- At the FXS site he only hear a very small ring then it closes and if he try to pick up the call he cannot hear any thing except the normal tone.
4- The customer doesn't feel any thing and it still ringing.
5- At the FXS site it still give the tiny rings and nothing happen.

Any Ideas guys,

Thanks

 

[pndscm]

Give a little more information on your setup. Is it CME, CM, strictly VoIP FXS to FXO??????

 

[ahmedmid]

It works on cisco 2821 router with 4 Voice FXO interfaces and 2 Voice FXS interfaces. It Works with MGCP.

and I work on Cisco Unified CallManager.and the FXO works with GS(Ground Start) Ports.

do you want any other details.

 

[pndscm]

So the Gateway is registered with CCM using MGCP, Callers dial into the FXO port calling the analog phone on the FXS port and it doesn't ring correctly.
How does the incoming call get to the FXS port, directly or is there a Translation Pattern to get there?
What happens when an IP phone calls the FXS phone?

 

[ahmedmid]

The calls get directly, and the FXS is working fine with the internal calls but the problem with the external calls only. Is this can be problem with the C.O. ?

 

[pndscm]

Could be. You say you have 4 FXO's. Do all of them act the same or is only one messing up?

 

[whykap]

ground start trunks require a ground, so make sure the router is grounded to a tested ground (not just the rack but the router as well.

Also Ground start trunks are polarity sensitive, so reverse the tip and ring and test again.

 

[ahmedmid]

I tried to change the FXO port but it is the same at all ports and I'm sure that all connection is right and grounded well.