Unable to send FAX from remote site through IP link

[adaum]

I am unable to send a FAX from a remote site (G700) to the main site (S8500) over a WAN. The FAXes don't come out right or not at all. I understand this has to do with the conversion from TDM - IP and changed the IP-Codec fax field to pass-through, but faxes still won't go through, and ideas?

 

[FSI]

Have you tried the other options, too, beside pass-through? Also, did you add any redundancy?
We have the same issue in all our remote (G700) sites and none of the IP-Codec-Set settings resolved it, we also tested different firmware versions for the Medpros , created separate network regions for faxes so they can use G711 but nothing fixed it. We finally gave up and now sending out all faxes via local trunks on the G700

Regards,
fsi

 

[phonesrus]

With Faxing via VoIP you can generally do it under G.711 but you have to force the machines to transmit and receive in G-3 mode (9.6kb or less), newer machines default to G-4 mode (14.4 kb) and will fail most of the time. It is an issue with the transcoding sampling rate on VoIP and the rate of frequency changes in the fax tones at 14.4 kb., was the best answer I have ever gotten.

 

[adaum]

I finally gave up after changing all of the codec settings and called Avaya. The solution they gave me was to update the firmware on the medpro card, so we'll give that a shot and take it from there.

 

[bsmo]

On the codec set make sure you disable modem relay or passthrough because otherwise the G4 faxes will be recognised as modems and not faxes.

 

[nohuhu]

adaum,

faxes work over ip. but. first you need to make sure you're running cm with latest updates available for your version, update all circuit packs firmware (including t1/e1 and analog, if appropriate) to the latest supported version, and only then you should setup codecs and such.
i second to bsmo, you need to disable modem relay completely. as for faxing protocol, we got acceptable results with t.38.