Fax Send&Receive Problem

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Sep 2nd, 2009
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We have 2801 CME router. Also I connected a fax to this CME. But it gives communication error when sending fax and sometimes receiving. I tried with ATA and FXS ports but still the same problem. When I connect an analog phone to this line I can make calls and receive calls. Also when I connect directly analog line to fax (no cme) it works no problem. What can be the problem ? (Also I tried with two faxes) Can there be a software bug?


(C2801-SPSERVICESK9-M), Version 12.4(20)T1, RELEASE SOFTWARE (fc3)

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Nicholas Matthews Thu, 09/03/2009 - 04:39
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You can try this on the line:

input gain -3

output attenuation 5

Sometimes this configuration helps.


DONALD HEERING Mon, 09/28/2009 - 22:38
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FAXes can be particularly picky when it comes to line quality. Especially G3 faxes are a nightmare in an IPT environment.

I've been able to get some faxes working by disabling ECM (error correction mode) on it. As far as I know, this is only for sending. So this means that someone trying to send a fax to one of your fax machines would have to disable ECM on theirs.

See also http://www.voipmechanic.com/faxsettings.htm for some background.

Hope this helps!

Best regards,



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