Fax machines do not receive with VG224

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Nov 26th, 2008
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I have fax machines from Pitney and Ricoh behind a VG224. The Ricoh unit will intermittently not receive...it rings but does not pick up or fails handshake. The Pitney unit gives a fast busy signal. The Ricoh has been adjusted to begin communications at 9600, but the problems still exist. What can be adjusted in the VG224 to support the fax communication?

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Keith Fulcher Tue, 12/02/2008 - 05:24
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It depends on which protocol you are using (SCCP, MGCP) but you should configure the Fax Passthrough commands. I would list them, but it varies per protocol.

Nicholas Matthews Fri, 12/12/2008 - 12:14
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First try normal voice calls by hooking up a normal analog phone and make sure that your problem is 100% related to faxing. If analog phones fail, you will need to troubleshoot a normal voice call.

If normal phone calls work fine, try adding these commands:

voice service voip

fax protocol none

modem passthrough nse codec g711ulaw

Nicholas Matthews Mon, 03/02/2009 - 14:55
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Hi Doug,


mgcp modem passthrough voip mode nse

mgcp modem passthrough voip codec g711ulaw


b.orth Tue, 03/03/2009 - 07:41
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Hi Nick,

I am also having intermittent fax problems.

We have high volumes, usually 500 plus faxes per day. About every 2 weeks we get between 5 and 10 complaints of "incomplete" faxes. For instance: it should be a 10 page fax... we get 5 pages, but the sender does not get an error sheet. We are running CUCM 4.2(3).

Any ideas? or do you need more information?



Nicholas Matthews Tue, 03/03/2009 - 08:07
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Hi Bob,

Very hard to say. You could have packet loss/jitter in your network, or slips on your T1s.

Those are you big ones.

You could also try disabling ecm:

no mgcp fax ecm


b.orth Tue, 03/03/2009 - 08:41
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Hi Nick,

Funny that you mentioned T1's slips and packet loss/jitter, that is where I was starting to look for problems. I will keep a close eye on those.

I also noticed we can not set network clock on the VG224's like we do on 3845 gateways. Is that not necessary?

I am using fax pass through on the VG224's, and have "no mgcp fax t38 ecm".

In my version of code I do not see "no mgcp fax ecm".

Thanks for the tips, I will let you know about the T1's and network.




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