VOIP Faxes?

[D_L_P]

I have a customer using a Cisco Phone adapter plugged into a fax. They are having errors sending about 40% of the time but some receive errors as well. We swapped fax machines just to prove it wasn't our equipment and sure enough the new fax still gets errors. I just found out today out others in the building using the same setup are having problems. They still don't want to believe it isn't our equipment. Honestly, their IT department is useless and so I think they are passing the buck.

Has anyone ever ran into problems using VOIP to send faxes? Is there any settings on the adapter that help with faxing?

[RRodgers]

I have a customer using a Cisco Phone adapter plugged into a fax. They are having errors sending about 40% of the time but some receive errors as well. We swapped fax machines just to prove it wasn't our equipment and sure enough the new fax still gets errors. I just found out today out others in the building using the same setup are having problems. They still don't want to believe it isn't our equipment. Honestly, their IT department is useless and so I think they are passing the buck.

Has anyone ever ran into problems using VOIP to send faxes? Is there any settings on the adapter that help with faxing?

Try turning ECM off on the fax.

[907tec]

Agree with RRodgers: try turning ECM off. As far as I can tell, there is no reliable way to get fax and VOIP to play nice. The KonicaMinolta Solutions Database has a pretty lengthy submission on the subject: most of the workarounds include decreasing the transmission speeds and removing error correction. Basically simplifying and slowing down the transmission in every way. Good luck explaining that to the IT people, though...

[zed255]

I agree that basically 'dumbing down' the fax machine is going to be required. I don't think VoIP has the quality required to reliably transmit the relatively high frequencies used for fax transmissions. You can also try adjusting the equalizers to see if boosting the HF will help. Analog communication over digital media (and yes, I'm aware the phone system from the CO on is digital, but at a higher quality than VoIP).

[TheOwl]

We used to have a lot of problems in our office with those CISCO ATA Adapters until our internal IT people did a firmware upgrade of all of our phones, ATA Adapters and the call management system. Now everything works without an issue for all faxes and MFD's that are around Australia within our company.

Just as a suck it and see approach, you could try disabling J-BIG Compression and v.34, but I doubt that they are your problem. Hopefully the attenuation on the line is correct as well.

There could also be a chance that there is a bad line amongst everything which your faxes are picking up every now and then. This would also give a similar looking fault but still isn't the machines fault.

Otherwise, save yourself the hassle by packing the machine up and taking it with you because it isn't your fault that the IT people don't want to help. lol

[jonhiker]

I have had mixed luck on VOIP and fax machines, the analog to digital conversion and other wise, just doesn't like to play well together. Turning off ECM, V.34, and slowing the speed down to about 14.4 has worked the best.

[mojorolla]

The only thing BUILT to run voip for fax is V38, which is still in it's infancy. If your mode is JBIG, you must leave ECM on for it to work properly. We have had a few issues and and find the following works best:
turn baud rate xmt and rx to 9600
turn V34 off
change compression to MMR. Some of the newer one default to JBIG