Solved Recommendation for fax ATA

[Lee Cramman]

I'm looking for recommendations for a Fax capable single port ATA adapter to use with 3CX.

As it's only a single unit I don't mind manual provisioning.

Our system is hosted and we have an SBC.

The recommendations on the support pages seem quite outdated / limited and prices seem to run a huge range. The cheapest I've seen as unsupported is the Grandstream HT801 but I'm a little suspicious of a piece of kit that costs so little (it's less than £30).

Thanks

 

[eddv123]

Hi Lee,

The Grandstream gateway/ATA range will be supported in the next service pack update. It has not been disclosed what models will be supported however.

With that being said for FAX I would recommend you purchase a proper gateway. I personally have had mixed success with ATA's which claim to support FAX/T.38 in the past so would recommend you spend a little extra money for the extra piece of mind.

I would recommend the Patton 4112 JS device, it is fully supported and will do the job perfectly fine:
https://www.patton.com/voip-gateway/sn4110/

FYI Fax is only supported with 3CX in the local subnet or locally routed subnet. It will not work at all across the SBC or using STUN (in case you envisioned using it in this way).

 

[Lee Cramman]

Thank you for the recommendation. I had looked at that device before I posted but thought it was a bit of overkill for our needs and is also a little difficult to source in my region.

My supplier said that the Patton SmartNode SN101 would work with 3CX but I can't see any mention of anyone ever having tried it.

I gather from reading lots of other posts that getting fax machines working with VOIP can be a bit of a dark art... I was expecting to have to do a bit of fiddling to get things working.

Could you elaborate on what you mean by only being supported on the local subnet? I had envisioned manually provisioning, missing out the SBC and doing a bit of network jiggery pokery to map the necessary ports. If 3CX can't do this I might have to go back to the drawing board .

 

[eddv123]

I have tested the SN101 and where I don't like to say anything bad about Patton (they are great products) I could never get it to work with FAX, and support did not offer any reliable assistance either.

With that being said the SN101 is a white labeled product the SN 4110 series run Smartware so are fully Pattons own range.

In support of the Grandstream I have heard of resellers who say they have got FAX working with this device but I cannot offer insight on personal experience as I have only used it for FXS handsets only.

In regards to location look at this guide:
https://www.3cx.com/voip-gateways/patton-smartnode-sn4112-fxs/

It states in as a caveat:

"The device must be local to 3CX, in the same subnet and/or locally routed subnet (including site to site VPN)".

And I did in fact test this once myself 3CX >> Remote FAX using STUN but got an error in the logs to state that the FAX device was out of the local LAN.

As for setting up FAX it is not that bad but you do need to understand a few things (on top of the 3CX points above):

* Limit the amount of conversions: If you consider that a VoIP gateway converts T.30 signals from analogue to IP, then at best routes across an IP network and at the other end the other gateway converts back T.30 this takes time and could cause packet loss, the more conversions added (for example if routing over a provider network/PSTN this adds more conversions and thus further delay.

Delay will cause you issues with FAX.

* Find a provider who supports T.38 FAX. Your options in 3CX are T.38 FAX or G711 relay. G711 is quite bandwidth hungry and does not offer fall back options as well as being sensitive to delay, jitter and packet loss.

* If sending a FAX does not work, check a FAX to a different location, does an FXS call work through this gateway, if you have an analogue line available does a direct FAX across this work.

One thing you might also want to consider is if your customer is not 100% in need of FAX (for example some firms still require FAX for legal reasons) you should look at implementing an online FAX service instead.

 

[leejor]

A number of forum members have used the SPA112 from Cisco, which are not expensive. You will have to manually provision it, but it is not that difficult. Do a Google search of the 3CX Forums "3CX SPA112 FAX", for a number of posts on the subject.

Fax over an SBC is not supported however, you'd have to run over VPN

 

[Lee Cramman]

Thanks for the comprehensive answer eddv123. My provider supports T.38 and I think I'm pretty optimised as far as delay goes. However, the local subnet thing might well be the killer. I know little to nothing about setting up a VPN server on Debian and a production server probably isn't the place to learn .

Sadly, online faxing isn't an option. The information is medical and not only are there very strict governance rules in the organisation about outbound faxing, I've also been told it would also mess with the workflow too much. Oh how I wish we could just throw all fax machines away .

leejor, thanks but it sounds like the Cisco would have the same subnet issue.

So, short of learning to VPN it looks like my only solution is moving the PBX out of the cloud and into the office. Or keeping a POTS line just for faxing .

I wonder if 3CX will ever have a solution to this one...

 

[complex1]

So, short of learning to VPN it looks like my only solution is moving the PBX out of the cloud and into the office. Or keeping a POTS line just for faxing .

So the issue is only for outbound faxing?

Why not a separate or extra VoIP line for the fax?
This you can directly connect to the ATA, no 3CX involved.
You can keep your PBX in the cloud, no SBC or VPN have to be used.

This is just a thought.

 

[eddv123]

So I would agree, your only options are VPN or keep an analogue line for the FAX (I think this would be the easiest in this case).

If you do want to explore the VPN option, here are a few links to information reference VPN'ing to cloud instances:

https://cloud.google.com/vpn/docs/how-to
https://cloud.google.com/solutions/automated-network-deployment-multicloud
https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpn-connections.html

 

[Lee Cramman]

Thanks guys that's given me a bit to think about.

I hadn't thought about using Google to serve the VPN, I had visions of having to install OpenVPN on Debian alongside a 3CX install PBX - the thought makes me twitch.

At least I can now experiment safely...

 

[eddv123]

You don't need Open VPN for this no. You can now build a VPN from Google - this hopefully will give you an option that is acceptable.

 

[leejor]

As @complex1 suggested, if it's just for outgoing, why not just use an ATA with the fax machine? It's a matter of one trunk/line, possibly from the same provider that supports the PBX. Les cost than a landline and the bill bill be rolled into the existing one

 

[Lee Cramman]

As @complex1 suggested, if it's just for outgoing, why not just use an ATA with the fax machine? It's a matter of one trunk/line, possibly from the same provider that supports the PBX. Les cost than a landline and the bill bill be rolled into the existing one

Yes, I am considering that as an option thanks.

 

[cobaltit]

For reliable (and secure) faxing we only make one of two recommendations for our customers:

- Get or keep the analog line.
- Use a store and forward type fax ATA which resolves the T.38/internet connection issues.

The only thing we use for faxing in 3CX is light use fax DIDs for individuals. Main line or anything critical we do the above.

 

[Lee Cramman]

Just to update the thread in case anyone is interested or finds this useful in future.

I took a punt on one of the Grandstream HT801 devices on the basis that 3CX are adding support for Grandstream kit and that I could probably manually configure it if I couldn't get it to work with 3CX. It helped that it was extremely cheap and pretty much disposable if it didn't meet my needs .

My deployment isn't for a few weeks so I decided to give the new beta a spin knowing that there were some new ATA templates in there for Grandstream devices that might be worth a try, not to mention a new section for "Fax extensions".

And lo and behold not only did it work but, completely contrary to everything I've heard or read, it was perfectly happy to work via an SBC and did not need to be on the local subnet.

Bizarrely, I had to configure the extension as a 'normal' extension rather than a fax one but other than that it was ridiculously easy.

Happy days

 

[eddv123]

Most gateways and ATA's will work via the SBC if the registered to the SBC - you simply point the registrar address at the SBC instead of 3CX's local address.

If you are saying you have FAX working across the SBC then it would be because you have "fudged" the connection with a standard extension and not used a FAX extension - if you try and use a FAX extension remotely 3CX throws up an error about keeping it local (unless they have changed anything in the new BETA that I am not aware of).

Good to hear this is working however be aware of a couple of things:

* Too many FAX conversions will cause delays and thus could cause issues when sending FAX's.
You are converting from FXS to IP, across an SBC to a remote system, then out to the trunk across the net to your destination (it could potentially be getting converted across to the PSTN also).

* Without a FAX extension you will not be able to select between T.38 and G711 pass-through on the
I would imagine 3CX is just sending through what the Gateway is sending.

* You have done this manually I would of thought (as there is not way to select SBC in the FXS interface for the Grandstream - if it resets you will need to reconfigure from scratch - more of an issue for the larger gateways 16 ports +

 

[Lee Cramman]

Most gateways and ATA's will work via the SBC if the registered to the SBC - you simply point the registrar address at the SBC instead of 3CX's local address.

If you are saying you have FAX working across the SBC then it would be because you have "fudged" the connection with a standard extension and not used a FAX extension - if you try and use a FAX extension remotely 3CX throws up an error about keeping it local (unless they have changed anything in the new BETA that I am not aware of).

Good to hear this is working however be aware of a couple of things:

* Too many FAX conversions will cause delays and thus could cause issues when sending FAX's.
You are converting from FXS to IP, across an SBC to a remote system, then out to the trunk across the net to your destination (it could potentially be getting converted across to the PSTN also).

* Without a FAX extension you will not be able to select between T.38 and G711 pass-through on the
I would imagine 3CX is just sending through what the Gateway is sending.

* You have done this manually I would of thought (as there is not way to select SBC in the FXS interface for the Grandstream - if it resets you will need to reconfigure from scratch - more of an issue for the larger gateways 16 ports +

Yes, I have fudged it but from what I've read getting fax to work reliably across a SIP trunk is usually a fudge of some sort.

Too many conversions shouldn't be an issue, there will only be a single outgoing fax (one too many if you ask me) for occasional use. I am indeed using G711 passthrough and not T.38.

I'm not sure what you mean by manually provisioning as you don't seem to be able to auto-provision an ATA - even the 3CX guide has you uploading the XML file, sort of semi-auto... I simply provisioned it in 3CX, downloaded the XML from the provisioning link, uploaded it to the ATA and then added in the SBC IP address.

 

[eddv123]

Yes I mean manual configuration. If you wanted to auto-provision this device from 3CX as you have said you would have to generate the template as standard and then make some custom adjustments to suit the network changes (local IP to SBC address etc).