?
Solved

Asterisk Fax T.38 Support Explained

Posted on 2009-04-08
8
Medium Priority
?
2,683 Views
Last Modified: 2013-11-12
Could someone explain this to me:

"Asterisk 1.6 support G.711 and T.38 FAX origination and termination. T.38 gateway features are still in development. "

What is gateway features?  What will Asterisk 1.6 actually support with faxing, in layman terms?  Real world scenario examples would be helpful.  Thank You!
0
Comment
Question by:jkockler
  • 4
  • 4
8 Comments
 
LVL 16

Accepted Solution

by:
ai_ja_nai earned 2000 total points
ID: 24107130
A fax gateway is a facility that collects all the in/outcoming traffic and routes it to the right places, instead of letting the clients do it in their own place.

In practical scenarios, a T.38 fax call has at least part of the call being carried over PSTN, although this is not required by the T.38 definition, and two T.38 devices can send faxes to each other. This particular type of device is called Internet-Aware Fax device, or IAF, and it is capable of initiating or completing a fax call towards the IP network.

The typical scenario where T.38 is used is - T.38 Fax relay - where a T.30 fax device sends a fax over PSTN to a T.38 Fax gateway which converts or encapsulates the T.30 protocol into T.38 data stream. This is then sent either to a T.38 enabled end point such as fax machine or fax server or another T.38 Gateway that converts it back to PSTN PCM or analog signal and terminates the fax on a T.30 device.
0
 
LVL 4

Author Comment

by:jkockler
ID: 24107722
Great explanation!  Thanks!

Now just a bit more information and I should be good.

I am running Asterisk 1.4.23 which supports T.38 pass through.  Is this enough to get 2 fax machines to talk to each other?  Or should I upgrade to Asterisk 1.6, which supports origination and termination?  I would just test it but the fax machine I have right now doesn't work real well in general, so it is not a good test of function for the Asterisk box.  Thanks Again!
0
 
LVL 16

Assisted Solution

by:ai_ja_nai
ai_ja_nai earned 2000 total points
ID: 24108035
From version 1.4, Asterisk supports T.38 negotiation for SIP users, and the related passthrough of UDPTL T.38 data. This allows many T.38 nodes to communicate through an Asterisk box. Asterisk 1.4 does not, however, understand the T.38 protocol. It cannot terminate T.38 calls, or act as a T.38 PSTN gateway without external support - i.e. by passing the T.38 data to something which can perform those functions.
0
Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 
LVL 4

Author Comment

by:jkockler
ID: 24108214
Ok but What does terminate T.38 calls mean?  What is T.38 origination and termination?
0
 
LVL 16

Assisted Solution

by:ai_ja_nai
ai_ja_nai earned 2000 total points
ID: 24108827
it's the capability of creating and destroying telephone sessions
0
 
LVL 4

Author Comment

by:jkockler
ID: 24109496
Oh ok, so if the fax machine originates and terminates the call, then there should be no problem with 2 fax machines talking across an asterisk 1.4 box, right?  
0
 
LVL 16

Assisted Solution

by:ai_ja_nai
ai_ja_nai earned 2000 total points
ID: 24110351
yes, because 1.4 can passthrough the calls, but not start and terminate on its own
0
 
LVL 4

Author Comment

by:jkockler
ID: 24112911
That's awesome.  So Asterisk 1.6 can actually send a fax document directly to a fax machine, from itself.  That is really cool.  Thanks man!
0

Featured Post

The 14th Annual Expert Award Winners

The results are in! Meet the top members of our 2017 Expert Awards. Congratulations to all who qualified!

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

The purpose of this article is to demonstrate how we can use conditional statements using Python.
Fine Tune your automatic Updates for Ubuntu / Debian
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.
This demo shows you how to set up the containerized NetScaler CPX with NetScaler Management and Analytics System in a non-routable Mesos/Marathon environment for use with Micro-Services applications.

569 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question