atcomsystems.ca/forum Forums General General Telephone & Systems Information Fax on SIP?

I have a NEC SV9100 customer with some fax machines connected to the 9100 as analog single line extensions. Service is provided through a PRI.

Currently, the faxes work fine. We're looking into changing to SIP trunks. Will faxes work ok as single line ports accessing SIP trunks? Or should I go with the web fax, efax, fax bridge options that the SIP providers are offering?

Thanks.
Jim

Hi Jim,

If faxes are of any significant importance to this customer I would go with one of the options the SIP provider is offering. Fax over SIP is almost always less reliable than fax over POTS, and especially less than PRI. Longer faxes (more than 3 pages) are more prone to failure over SIP.

That being said, we've also seen low volume fax customers with short faxes be totally fine with fax over SIP.

Thanks, Toner. Kind of what I expected.

I looked at some FXS fax adapters, or ATA's. Cisco and Grandstream makes some. But that introduces another device. Probably worth the extra for the efax service to elminate the issues. Biggest problem is getting the customer to change!

We're setting up efax services due to ongoing conversions to VoIP. And, since switching to SIP trunks (in PRI form) about a year ago in our legacy system faxing failures have become common. I have a demo account I've been testing with. One difference is the process at the fax machine. After scanning the document the result is displayed as 'Completed' - when it really isn't. All Completed means is that the document has been received by the efax server via the internet. The process will take at least as long as it previously did when the fax machine dialed the receiving fax number - it rang, answered then transmitted the fax. It will be something customers will need to get used to.

On the 'Fax Console' computer app the status can be watched with statuses of Sending and Completed (or occasionally Busy). I asked our potential vendor if a similar status could be provided on the fax machine itself as not everyone faxing will have access to the Fax Console. I was told there is a related option for the machine itself, we'll see how that turns out.
'

Be careful about HIPAA compliance if you do efax (you need to include your email in this compliance). Also, make sure on your fax volumes, efax can be VERY expensive depending. Honestly I have found, doing a LOT of doctors etc the cost of a single line from Comcast on an EMTA is cheaper and compliant. EMTA is not Voip there fore your fax/modems work.

FYI...We have Intermedia SIP Trunks on CP-10 & CP-20 CPU's. Per NEC, on CP-10, 84-33-01 for SIP Trunks are Enabled and on CP-20 they are Disabled. We migrated over a CP-10 to a CP-20 and the Fax machine would drop the call. This was the culprit. Hope that helps...