Configuracion Fax Pro


Soy nuevo en esto de freepbx, queria preguntar si alguien me podria ayudar en configurar el modulo Fax Pro, lo que requie es tener una maquina de fax conectada a freepbx y ese fax sea reenviado a otro numero de fax, si alguien me pudiera ayudar con esto.

Just to understand what you’re asking. You want a single incoming fax to be received by two fax devices?

Solo para entender lo que estás preguntando. ¿Quiere que dos dispositivos de fax reciban un solo fax entrante?

no, es para conectar una maquina de fax a freepbx y enviar el fax a un numero de fax (fuera de freepbx)

no, it is to connect a fax machine to freepbx and send the fax to a fax number (outside freepbx)

Faxes don’t work that way, you will need to ‘store and forward’ either the complete and decoded T30 or T38 transaction or get yourself out of the loop processing the fax, this can only be done by redirection of the inbound call before even answering it or converting the raw g4 or whatever document after successful reception as another separate fax.

So do I need to store the document ?
then manually send the document?

You need to ‘store then forward’, that can be done manually or you can script it if you have methods to both send and receive faxes.

ok, can you help me with that?, because I’m new to freepbx and I don’t understand very well. for example i have configured inbound and outbound routes with sip trunk.
I have an extension that receives faxes and sends them by email, but the fax is received by twilio number and I want to connect a fax machine to send to another fax number

No I can’t if the fax is received by Twilio, it would need Twilio to forward it. If you receive faxes as email’s then it is up to you to forward them by whatever means makes sense.

yeah, but the only twilio do is just forward it to freepbx through the extension, because twilio removed the fax service

and i need connect a fax machine to freepbx and send fax to another fax number

I haven’t used FAX with Asterisk, but, in theory, shouldn’t it just work, in real time if you use G.711 codecs end to end and there are no excessive delays or corruption/loss of data. It ought not to be a problem with analogue or ISDN, but SIP might impose excessive delays and data loss.

There is also T.38, of which I know little, except that it tries to address VoIP limitations. In particular, and don’t know if it is possible to have analogue modems at both ends with a T.38 hop in the middle, and if it is, whether Asterisk supports it, although I know that that the equivalent used to done transparently for transatlantic faxes.

Further research suggest this is called fax relay and is supported by T.38.

I’m surprised that FAX is still in use. I the UK, I think general medical practitioners (GPs) were the last holdout, but I think even they send files by computer, now. A consequence of this is that relatively few people will have any current knowledge of relaying fax through Asterisk VoIP.

Some further explanation as to whey FAX over VoIP is difficult can be found in FaxOverIP

I don’t think Fax Pro is relevant to your requirement. It looks to me to be more of a fax to email gateway.

The problem is that not much is known about a fax at the time it is detected by the 2100Hz CNG tone and then responded to Faxes come in a huge number of flavors, to successfully handle the call , it thus must be answered, now Asterisk can ‘pass-through’ T38 to an ATA or pass it through ‘soft-modems’ that synthesize FAX machines and that handles the various methods of transport and error detection/correction. It could also not respond to the CNG and just redirect the call, the Catch-22 here is that without processing the “Fax Header” which comes at the start of the transmission, not much is known about who or where the fax was directed or where it came from.

Probably easiest answer here is manually reading the fax and re sending it after using some AI (I is probably all that is needed)

Either a Commercial FAX forwarding service or, with a lot more effort, Hylafax with T38 soft modems are probably the only ways to provide all the tools to automate all the above with a reasonably high success rate, Asterisk is just not up to the task

CNG tone is 1100 Hz. 2100 Hz is answer tone/echo suppressor disable tone.

I think you are over-thinking this. I think they just want a dedicated DID on which they hang a legacy fax machine.

In my world a call that originates with a 1100Hz sine wave (my typo thanks) is signalling a request for a digital over voice answer, further conversations isolate specifically a FAX which sends a particular cadence with our without FSK that qualifies it to be called as CNG and not other data, any reply at 2100Hz is usually known as the CED

I don’t think I’m overthinking it as the OP explicitly states

no, it is to connect a fax machine to freepbx and send the fax to a fax number (outside freepbx)

And having done once thousands but still hundreds/dozens of T38/T30/mail2fax/fax2email pages a day including retrying re-forwarding and broadcasting successfully over analog/TDM/SIP and on occasion H323, I believe I know what thinking is needed.

As always this is JM2CWAE

thanks all for your help, can someone tell me how to create an outbound route for an extension connected to a fax machine?

One doesn’t create outbound routes to extensions. Do you mean a Misc Destination?

Is the destination fax machine an extension, in FreePBX terms? It’s been pointed out that your original request was for PSTN number, not an extension.

On re-reading the thread, the calling fax machine appears to be on an extension, so I’ve changed the following.

In terms of routes, the external fax machine is just the same as a PSTN voice number.

However the trunk may require special consideration. If you are using chan_dahdi, it will probably not need anything special either, but if you are using VoIP, you have two options, and you will need a very good internet service.

Firstly you can try to be as close to analogue as possible and make sure that you only use ulaw or alaw codecs, according to your country. Alternatively you can try to use T.38, for which you will need support from your provider. I have no experience of T.38, so can’t help you there.

If you are using VoIP, then either you will need an ATA to connect the local fax machine, or you will be using a VoIP fax machine, which may require T.38. The ATA is probably where you would convert to T.38, if using that. If not, it will need to be limited to ulaw or alaw, as above.

yeah, its a fax machine connected with an adapter (real hardware) and i need to send a fax from freepbx to another fax number (outside freepbx).
sorry, im new with freepbx, i have 2 weeks learning about freepbx, to me only said them “you have todo that”

The outbound route is not special.

Most of the problems are related to VoIP, not to FreePBX.

Option 1, make sure that adapter is set to use ulaw or alaw and make sure that the trunk is also set to that. DO NOT use gsm or g729. This may work if you have a good internet and VoIP service.

Option 2, enable T.38 in the adapter. Make sure the provider supports T.38. Configure the adapter extension, and the provider trunk for T.38 pass through. I can’t help you on the details. If you can get this to work, it is likely to produce much better quality transmissions.

If you are in Spain, you should use alaw. If you are in the Americas, you should use ulaw.

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