Solved

Asterisk Fax T.38 Support Explained

Posted on 2009-04-08
8
2,664 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
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 4
8 Comments
 
LVL 16

Accepted Solution

by:
ai_ja_nai earned 500 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 500 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
Ransomware-A Revenue Bonanza for Service Providers

Ransomware – malware that gets on your customers’ computers, encrypts their data, and extorts a hefty ransom for the decryption keys – is a surging new threat.  The purpose of this eBook is to educate the reader about ransomware attacks.

 
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 500 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 500 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

What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Linux users are sometimes dumbfounded by the severe lack of documentation on a topic. Sometimes, the documentation is copious, but other times, you end up with some obscure "it varies depending on your distribution" over and over when searching for …
Almost all Internet protocol telephones have built-in switches at the back that allow you to connect your personal computer to one port and use the other port to connect your phone to to a Cisco switch.   Why we need to connect the PC to the pho…
Learn how to navigate the file tree with the shell. Use pwd to print the current working directory: Use ls to list a directory's contents: Use cd to change to a new directory: Use wildcards instead of typing out long directory names: Use ../ to move…
How to Install VMware Tools in Red Hat Enterprise Linux 6.4 (RHEL 6.4) Step-by-Step Tutorial
Suggested Courses

738 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