Register a SA Forums Account here!
JOINING THE SA FORUMS WILL REMOVE THIS BIG AD, THE ANNOYING UNDERLINED ADS, AND STUPID INTERSTITIAL ADS!!!

You can: log in, read the tech support FAQ, or request your lost password. This dumb message (and those ads) will appear on every screen until you register! Get rid of this crap by registering your own SA Forums Account and joining roughly 150,000 Goons, for the one-time price of $9.95! We charge money because it costs us money per month for bills, and since we don't believe in showing ads to our users, we try to make the money back through forum registrations.
 
  • Locked thread
SSH IT ZOMBIE
Apr 19, 2003
No more blinkies! Yay!
College Slice
Uhh - anyone running FOIP over T.38 + SIP via an internet VOIP provider in a production environment?
Trying to do FOIP over g.711 over the internet seems like insanity, is T.38 less insane?

Most fax software instead use proprietary solutions and cloud connectors, which are much more expensive. My place of employment is being cheap in the wrong places so I am trying to think of workable, cheap solutions.

Long story short our local telco providers aren't very well connected with the rest of the state, and seemingly can't port a lot of external numbers from other carriers so we can't get take inbound calls over over T1s.

I'm thinking about hacking something together with Brooktrout's SR140 software + a more well connected T.38 enabled VOIP provider, but I'm questioning if it's even a good idea worth looking into.

I'm not really a telecom guy, though the basics I understand, enough to build\maintain\support our current software fax solution.

Adbot
ADBOT LOVES YOU

wolrah
May 8, 2006
what?
I'm doing it for a few customers using Asterisk with SPA112 ATAs. It works mostly, but troubleshooting T.38 is definitely not as well documented nor do all providers support it properly. If your outbound calls run through a LCR system at any point its possible that some of the paths it might take support T.38 properly and others don't, causing intermittent fallback to G.711 with all the problems that brings.

Personally I prefer store-and-forward systems that don't try to actually connect the ends together in real-time. The adapter box pretends to be a fax machine and receives the entire document to memory, sends it to the upstream system as basically a file transfer over TCP, then the upstream system either dials out to the PSTN or passes the document along to the next hop as necessary. Unfortunately those seem to be pretty much proprietary. The implementation of this I'm most familiar with uses Audiocodes MP202 ATAs and communicates over HTTPS. It works great when it works but the provider I use is basically a black box when things go wrong.

At this point we try to avoid getting involved with fax. If a customer wants fax we first try to convince them that email is better for everything. If their industry is still stuck in the '80s and they can't just abandon that garbage we push them towards e-fax solutions, then if they have the kind of users who just insist on using an actual physical fax machine we recommend a plain old POTS line.

wolrah fucked around with this message at 00:22 on Mar 13, 2016

SSH IT ZOMBIE
Apr 19, 2003
No more blinkies! Yay!
College Slice
Gotcha. Thanks. So might not be a good idea even if it seems OK on paper.

Toe Rag
Aug 29, 2005

I'm not sure what you mean by saying your telco providers aren't "well connected enough" to port your numbers from other carriers. LNP works through a 3rd party database (eg, Neustar) and doesn't require any degree of connectivity on your providers part, other than being able to "understand" when it receives a call to a ported number. That's all standardized and legally mandated, though, so it shouldn't be a problem.

I haven't really worked with voice in 6 years, but all your voice and fax calls are likely being converted into VOIP on the backend anyway. TDM switches are going away everywhere except the end office. If you are trying to do faxing over a simple Internet connection, then you might run into trouble, but if you have SIP trunking with a service provider, they should be able to support it. That may be out of the budget, though, no idea.

Alereon
Feb 6, 2004

Dehumanize yourself and face to Trumpshed
College Slice

Toe Rag posted:

I'm not sure what you mean by saying your telco providers aren't "well connected enough" to port your numbers from other carriers. LNP works through a 3rd party database (eg, Neustar) and doesn't require any degree of connectivity on your providers part, other than being able to "understand" when it receives a call to a ported number. That's all standardized and legally mandated, though, so it shouldn't be a problem.
The new provider has to have a switch in the same LATA (geographic area) as the number however, which isn't always the case for smaller providers. This can get really complicated in an area that straddles a LATA boundary.

adorai
Nov 2, 2002

10/27/04 Never forget
Grimey Drawer
we take inbound faxes over g711 and it works great if they terminate in a VOIP fax server (we use elastix). If I try to dump the calls out of an fxs port, it fails more than it succeeds.

Morganus_Starr
Jan 28, 2001
We partner with these guys: http://www.vitelity.com/services_vfax/

So far they have been pretty decent and cheaper than garbage like efax.com which is way overpriced. They have a little custom ATA you can hook up to your physical fax machine if you want. Or of course they have a web portal/APP you can use for e-fax, as well as the typical e-fax via email.

We've deployed our fair share of Cisco SPA112s also, just make sure if you put these behind a firewall and if they register to elsewhere across the internet you adjust the SIP re-register timers on them, and/or tweak your UDP NAT timeouts on your firewall to be less aggressive so you don't have any reg issues.

Also I just want to say gently caress faxing, and gently caress international faxing (hello international e-faxing, good luck finding a provider who REALLY supports this and does it well).

I'm afraid a POTS line is still the gold standard when it comes to faxing, at least from my experience.

FatCow
Apr 22, 2002
I MAP THE FUCK OUT OF PEOPLE

Toe Rag posted:

I'm not sure what you mean by saying your telco providers aren't "well connected enough" to port your numbers from other carriers. LNP works through a 3rd party database (eg, Neustar) and doesn't require any degree of connectivity on your providers part, other than being able to "understand" when it receives a call to a ported number. That's all standardized and legally mandated, though, so it shouldn't be a problem.

This couldn't be any far from reality.

Alereon posted:

The new provider has to have a switch in the same LATA (geographic area) as the number however, which isn't always the case for smaller providers. This can get really complicated in an area that straddles a LATA boundary.

Close. You need to be connected to the access tandem if you want inter-LATA calls to work from as well as the local tandem if you want intra-tandem calls to work. Sometime they are the same switch, but in larger LATAs there are often many local tandems you need to interconnect with. You don't need to have a switch in the LATA, you do need to generate a in-LATA CLLI, but it just references your actual switch. According to LERG my network only has three switches. And we're one of the largest footprint telephone companies in the US. There is a bunch more nuance to it, but that's the gist. All numbers are in a rate center and that rate center is in a LATA.

If you have a solid connection to your VoIP provider, and they are a quality provider, g711 will work just fine.

Toe Rag
Aug 29, 2005

Why? I'm not saying it isn't, but I am curious. LNP translation usually happens towards the origin of the call, right? If you have the correct LRN and keep the original dialed number intact, I don't get why it would need anything more from the receiving party network, but obviously I am missing something.

FatCow
Apr 22, 2002
I MAP THE FUCK OUT OF PEOPLE
Local and long distance calls are handled by different routing elements in the PSTN. If you call local the call will show up at the local tandem, if you call long distance the call will show up at the access tandem. Your network will need to have trunking in both places in order to receive the call.

Alereon
Feb 6, 2004

Dehumanize yourself and face to Trumpshed
College Slice
I was more looking at it from a porting perspective, you aren't able to activate a number in your network unless you have an LRN within the same LATA to activate it on. This is checked in the NPAC systems when you try to activate, and lack of LRN availability was one of the bigger barriers to porting I saw. But that was only my piece. I used to work for the company that made the porting application carriers (except the top-tier wireless ones) used to actually do the port and activation process, our servers interfaced with NPAC. "Why does it say every LRN is invalid for this number" was a pretty common issue for some reason.

Adbot
ADBOT LOVES YOU

Partycat
Oct 25, 2004

adorai posted:

we take inbound faxes over g711 and it works great if they terminate in a VOIP fax server (we use elastix). If I try to dump the calls out of an fxs port, it fails more than it succeeds.

This has not been my experience, g711 has been great inbound as long everything else is working well, as you don't get much error correction or anything with a real fax. Relay has been horrible. T38 works in network but I would dump to g711 at the border to avoid it myself. Various companies make appliances to grab the fax and relay it via email or something and drop it back out at the far end on contained provider networks.

  • Locked thread