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Telco dropping calls from analog gateway

g.chavez
Level 1
Level 1

We just changed carriers for our two PRI's. Since then our outbound only fax (analog) calls do not connect. We get a fast busy signal. We have worked with the carrier and they are getting the call but their switch is dropping the call. They said our analog calls come in as 3.1KHz audio and the non-analog calls work but they hit the carrier as "speech". The other issue they say it "might" be is that our analog "Calling_Num" is type and plan "unknown". Whereas the digital calls that work the "Calling_num" ISDN/telephony. Any ideas on how to get this changed or should the carrier be able to handle this?

1 Accepted Solution

Accepted Solutions

I think you should show this last trace to telco and ask how do they really want the call to be.

The succesfuk one, incoming, has bearcap 3.1KHz and called type/plan ISDN/unknown. Perhaps they want it that way. Perhaps they want all nine digits for local calling too.

I have not seen a trace of a succesful call from IP phone to the smae number, else I would compare to that as well.

By now I think you have understood how to change the call parameters.

View solution in original post

25 Replies 25

paolo bevilacqua
Hall of Fame
Hall of Fame

These parameters are easy to change. Tell us which gateway you have, and if you are using MGCP h323, which CCM release if you are using it. Someone on the forum can suggest how to configure.

We have a 2650 router with (2) 2-port FXO cards. We are using CCM 4.0. I believe we are using MGCP h323 but am not sure how to confirm.

Hi,

There is nothing you can change in FXO ports. Before you mentioned PRI and things that are ISDN, where are these?

Our PRI's come in on a 3745 router. We have two CCM servers and the 2650 router with the FXO cards for use as the analog gateway.

Ok, all the things telco said (3.1 Khz/speech/numbering type and plan) apply to PRI only. If you have problems with these, we can help you change the parameters.

On the FXO ports there is nothing you can change, and if telco is complaining about the things above said on analog lines, either there is a gross misunderstanding, or they are taking you for a ride. FXO ports are the one that go into the wall plug, that is telephone lines.

Perhaps you mean the fax machines are connected to FXS ports ?!?

Let me clarify. We are using channels on their PRI to send analog calls. We do not have any 1FB(analog) lines from the Telco. All inbound fax and digital call work. All outbound digital calls work. All calls go thru the PRI. However, outbound faxes are leaving our network and are being received by the Telco on the PRI. But they are being received as 3.1 audio format. Outbound analog calls are the only thing that is not working. I assumed that changed would be on the 2950 since that is our analog gateway. That gateway must somehow route back to the 3745 to go outbound on the PRI. Make sense?

Ok, so the 2950 has 4 FXS ports connected to fax machines, correct ?

Now, depending on how the two routers and the CCM are configured, there can be more that one place to apply the changes to bearer capability (the 3.1 / speech parameter) and the plan type (the unknown/isdn parameter).

If you are unsure if using MGCP or h.323, post configuration, omitting public IP and telephone numbers, and someone can suggest the best thing to do.

Attached are 2950 and 3745 configurations.

OK. Indeed you have 4 FXS ports in the 2950 and are using h.323. The routers are quite accurately configured.

In the 3745, under serial 4/0:23 and 4/1:23 configure:

isdn outgoing-voice info-transfer-capability speech

and if calls still not going out:

isdn map address . plan isdn type national

Note: for the latter, make sure with telco that this is actually what they want for ALL calls. If your ability to place international calls is impacted by this, there are other configurations that can be done.

You can verify what parameters are in the call doing "term mon" and "debug isdn q931". With this, you will see also why telco is refusing the call.

Hope this helps, if so please rate post!

I entered the first command and do a show run but it does not show up and it still rings busy so I am not sure if it displays in the config or not? Any ideas?

hi,

the config should show up, try again. then the debug command above and "term mon" will tell you how is working.

I did that and it still shows as an audio call instead of speech and it doesn't show on the config. the switch type is DMA-100. Could that have something to do with it?

I think is not being configuring correctly. Are you familiar with "config terminal" mode ?

I am. Here is what I entered.

Config t

int ser 4/1:23

isdn voice .... speech (the command you gave me).

I repeated this for int ser 4/0:23

It returns to the #prompt.

Exit (twice) to get back out of config mode.

Then show run and it is not there.

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