Provisioning HT801 Fax extension

[Horatio]

Hi,

We are having issues provisioning a fax extension via a Grandstream HT801 and 3cx v15.5.

The ATA and fax machine is in a remote location however both office network and PBX are connected via a VPN.

Also normal extension can provision fine using username and password fine.

Has anyone had this issue?

thanks in advance.

 

[eddv123]

Hi Horatio,

I found getting this device to work for FAX a bit of a challenge. It is not in the supported list either so it would be a manual configuration as well: https://www.3cx.com/voip-gateways/

One thing you do need to know about VPN setup for gateways is that you need to configure a Default Gateway (as the device that the VPN is coming to/from as there was no route back from one subnet to the other. You will need to check the Grandstream for this parameter.

Unless it is crucial to the business however I would try and convince your customer to go with an online service going forward.

 

[Horatio]

Hi Eddv123,

Yes it has been a challenge..and yes not supported by 3cx but much cheaper that the supported options.

We tried configuring the gateway on the HT801 but no luck, we may try to just use a SIP trunk without 3cx or talk to the customer about online options.

thanks for you help.

 

[leejor]

In some cases, even though it should work, it is sometimes the particular fax machine, that is the problem. If you have a copy of the instructions, see if there are options they recommend if using on a VoIP line. Or... try an older Fax machine, if you have one available. Some newer models will not operate on a slower speed, which is sometimes necessary.

 

[eddv123]

To add, I have also had it in the past that the ring voltage on the line is not as high as it would be if using a standard analogue line.

In this case the FAX machine requires a ring capacitor adapter - this is quite common.

https://www.amazon.co.uk/Titan-LJ5109-EG-MICROFILTER-CAPACITOR/dp/B0040Y7AOG

 

[leejor]

If the fax machine answers the call, and it's going to be obvious if it does, then the ringing voltage is "doing it's job" on an incoming call. If the user is in the UK, where the ringer may not be bridged tip to ring, as it is in many parts of the world, then the adapter may be of use. I'm not certain how it would boost the ringing voltage however.

 

[eddv123]

If the fax machine answers the call, and it's going to be obvious if it does, then the ringing voltage is "doing it's job" on an incoming call. If the user is in the UK, where the ringer may not be bridged tip to ring, as it is in many parts of the world, then the adapter may be of use. I'm not certain how it would boost the ringing voltage however.

Leejor - to give you a bit of technical background.

I have had a couple of instances with customers where they have had issues with FAX being sent to a DID (via Patton's as this is our gateway of choice) when the FAX is sent it just rings and never answers - the device gets stuck on stuck on 180 Ringing.

After debugging the Patton https://www.patton.com/support/kb_art.asp?art=327& you would see:

Route to provider 'IF_FXS_00'
State RINGING, event PEER_CONNECTED

So the call is passed to the device(s), which do not have these adapters attached. It was only when adding them that the FAX works correctly.

 

[leejor]

Where many areas (and devices) use two wires, with the ringer bridged across tip to ring, the UK chose to use a slightly more complicated system with a master socket containing a capacitor and resistor, (along with a surge suppressor in most cases). This allows devices with 3 wires to have an operating ringer where the "bells", in the device is connected between the third lead (bell wire) and one of the others.

We used to use a similar method in North America, years ago, for one type of party-line service, when ringing was sent out over either tip or ring, with the other side of the ringer, through a capacitor internal to the set, connected to ground.

Since most VoIP devices are designed to be used anywhere in the world, they are therefore a two wire (tip and ring) device, to ring some devices designed to be used in the UK, you will then require either a "Master Socket", or a device such as you've put forward, which I assume does the same thing, in bringing a connection to the Bell Wire, #3 in the diagram. Without it, there is no connection to one side of the ringer, depending on the design of the device.

 

[eddv123]

For the sake of this ticket (and to confirm) this device works quite reliably for STUN to a remote hosted 3CX system, I got it working yesterday with an FXS end-point.

I will test for FAX also but highly doubt this would work for fax in this scenario.