VG224 voicegateway fax issue with international faxes

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Aug 3rd, 2010
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I use a vg224 with sccp & fax-protocol cisco. Faxes national work but with one international fax number it doesn't work. When i use a direct line it works.

I don't know what's going wrong. When i use a phone with the same css, i can call the fax. Receiving faxes from the international destination is no problem. Can anyone help me?

With kind regards


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Steven Holl Tue, 08/03/2010 - 08:28
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Does the voice call setup?  First thing to make sure is that you can bring up a voice call, before you worry about switchovers.

Is it an inbound or outbound international call that fails?  It could be the plan/type presentation of the number if it is failing outbound.  Look at your call signaling.

If the call is being established, it's a switchover issue, and if you can post your configs for the PSTN gateway and the fax gateway I can take  alook.

Also, I personally wouldn't recommend Cisco Fax relay, which which what is sounds like you are using.  If you're going to a Cisco PSTN gateway, you should use modem passthrough or T.38.


mgruyters Tue, 08/10/2010 - 01:35
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Hi Steve,

I tried modem passthrough. That didn't change anything. The problem accurs with slovakian numbers. The problem is from our costumer to slovakia. From slovakia to the costumer works. We tried also other slovakian numbers, they didn't work either. Faxes to other countries do work. (i tried Belgium & UK).

ISDN dialplan issue???

Steven Holl Tue, 08/10/2010 - 06:46
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I looked at the configurations, and I only see Cisco fax relay on the VG224, and nothing on the PSTN gateway.  Maybe you made the modempass configuration changes after this, but you should have:

You should first configure this for both devices:

On the VG224:

voice service voip

fax protocol none
modem passthrough nse codec g711ulaw

Yes, the issue could be an ISDN plan/type issue, if the call isn't connecting on that specific number.  You need to do some troubleshooting or run some debugs to find out where the fax is failing, and direct attention there.

Run the following debugs for a failure:

debug voip rtp session name

debug voip ccapi inout

debug isdn q931

krahmani323 Tue, 08/03/2010 - 09:27
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Hello Martijn,

I do not know if it can apply to your conditions, but I have been facing similar symptoms in the past. It was due to bug CSCsm49011.

CSCsm49011            Bug Details

VG224 SCCP port plays reorder before CM routes call-IOS interdigit timer

On an FXS port configured for SCCP usage  (such as on a VG224), reorder is heard 10 seconds after the last digit  dialed when a number is dialed that requires waiting for interdigit
timeout on CallManager.


Using SCCP controlled FXS port on an IOS box.
Dialing a number which requires waiting for interdigit timeout to route (such as a variable length international number).


Increase the interdigit timeout setting on each SCCP FXS port to 16 secs (to be greater than 
CallManager's 15 secs). This is done by configuring "timeouts interdigit 16" under each voice port.


decrease the CallManager interdigit timeout to 9 seconds (to be less than the VG224 port's 10 
secs).  This is done by changing the CallManager service parameter T302 Timer  value to 9000 msec (9 seconds). If this workaround is chosen the new  interdigit timeout setting will apply to all devices attached to the  CallManager, not just the IOS SCCP FXS ports.

Further Problem Description:

When  this problem manifests, the user hears reorder tone 10 seconds after  dialing the last digit. 15 seconds after the last digit is dialed (5  secs after beginning to hear reorder), reorder will stop and the call  will route, resulting in ringback tone. The reorder tone is a "cosmetic"  problem, but will lead most users to (incorrectly) believe there is an  actual problem with their call.

1st Found-In 12.4(4)T5 / 12.4(11)T6.....

Fixed-In / 12.4(19.3)T..

Best regards



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