Insight on Faxing over SIP

[AACon]

Just wanted to get anyone's opinion on FAX over SIP. It seems it is really hit or miss depending on the provider. Some swear up and down they support T38, when they don't, and only G711 works (barely). Others, it works awesome. I've had more misses, than hits with this lately, it seems. Sadly, I have no control over it. I get providers telling me "we can get fax tone, it works". Sure...from your *PHONE*, you get fax tone, but not from your FAX MACHINE YA GOOF! Why do people insist on putting fax on sip. why.

Any providers you've been able to successfully get faxing over sip working on? So far, only Flowroute for me.

-Austin
ACE: Implement IP Office

 

[IPOLackey]

We have had similar issues with Fax over SIP. We've found a more reliable route is to use an ATA like the Cisco SPA122. Works on all providers we've tried here in the UK.

 

[phoneguy610]

We use the Cisco spa 122 as well,what I have found is that it usually only works with newer fax machines with a t.38 or VoIP setting .

Basically every fax machine made within the last 2-3 years has this setting

ddcommllc.com
Avaya/Toshiba/SyntelSolutions

ACIS

"Will work for stars

 

[AACon]

That might be a good route in the future. So, you run these in tandem with the sip trunks on the system itself?
That's were the issue I have lies; SIP trunks on IPO, analog faxes off IPO.
We ended up getting the issue resolved. The provider, again, had to look at their settings and fix T38.

-Austin
ACE: Implement IP Office

 

[phoneguy610]

We are a sip provider so we usually have a sip trunk dedicated for fax ...i haven't connected one off an ipo before


ddcommllc.com
Avaya/Toshiba/SyntelSolutions

ACIS

"Will work for stars

 

[Jonjr88]

I resell SIP trunks (coredial) to many of my customers with many fax machines on IPO never had an issue!!

 

[phoneguy610]

Jonaron so are we but hide your source

Jeez

ddcommllc.com
Avaya/Toshiba/SyntelSolutions

ACIS

"Will work for stars

 

[AACon]

Ironically, the issues we had were with coredial trunks.

-Austin
ACE: Implement IP Office

 

[intrigrant]

The last time we had SIP - Fax problems was with release 6.0.
The only thing to know for sure is what protocol the provider prefferes T.38 or transparant G.711, I preffer T.38 as it seems to be more reliable but both works well if you have enough bandwith.

Know your product and become a Pro

 

[AACon]

Yeah I guess it really comes down to the provider. I had ZERO issues setting it up with one provider that I use for my sip trunks, but other's just cannot get their stuff together. I need to start intervening on these sales calls to divert them to known_working providers.

-Austin
ACE: Implement IP Office

 

[phoneguy610]

AAcon cd trunks work,but they usually work better with fax machines that are setup for t38

Also you need to make sure cd has them setup as a level 3 fax line or they won't work

ddcommllc.com
Avaya/Toshiba/SyntelSolutions

ACIS

"Will work for stars

 

[AACon]

Yeah that was more than likely the issue. Said something had to "change on their end". No biggie, it works, now i know what to yell at them about.

-Austin
ACE: Implement IP Office