[asterisk-users] T.38 fax solution, opinions?

[Matt Watson]

The fax machines will be talking directly to the spa2102 - the problem is
that Asterisk only supports being a T.38 pass-thru and not an end-point.  And
I need the ability to fax over WAN links like ADSL... so I'll have a fax
machine plugged into a Linksys SPA2102 which will connect to Asterisk over
ADSL, if I route the calls directly to the PRI and use G.711u for the Linksys
<-> Asterisk connection, then any hiccups on the DSL line are going to cause
the fax to potentially get screwed.  This is what T.38 is designed to fix...
but since Asterisk doesn't support being an end-point... you need something
else to do it... that could be a SIP provider that supports, t38modem,
another ATA, etc.

 

That's why our planned setup is way overly complicated... just to get T.38.

 

--

Matt

 

From: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Robert Augustyn
Sent: Monday, December 10, 2007 4:25 PM
To: 'Asterisk Users Mailing List - Non-Commercial Discussion'
Subject: Re: [asterisk-users] T.38 fax solution, opinions?

 

How about fax machines talking directly to spa2102 and then out the pri or am
I missing something?

	 

________________________________

	From: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Matt Watson
	Sent: Monday, December 10, 2007 4:06 PM
	To: Asterisk Users Mailing List - Non-Commercial Discussion
	Subject: Re: [asterisk-users] T.38 fax solution, opinions?

	I;m not sure how your solution would work... but I thought I'd throw
out some ideas that we are having to implementing faxing here on a new
install.

	 

	We are going to be bringing in a PRI and routing all the DIDs from
our existing copper lines to the PRI (including fax DIDs)... the solution we
are working towards is certainly not ideal, but we are hopeful its going to
work...

	 

	Incoming fax calls will come into Asterisk, asterisk will route them
to IAXmodem which will feed Hylafax (all running on the same box as Asterisk
to reduce latency... and we are talking about fairly small volumes).  Hylafax
will then do fax 2 email

	 

	Outbound faxing however is a bit trickier...

	 

	We are going to use Linksys ATAs (tested with a SPA2102) which will
have the POTS fax machines plugged into them, the SPA2102 connects to
asterisk with SIP, asterisk will then route the calls to t38modem (recent dev
versions of it support SIP and not only H.323), t38modem is basically just
like IAXmodem except its SIP and supports t38 termination.  T38modem will
again feed hylafax, which will then route back to asterisk through IAXmodem
and then up the PRI.

	 

	Its certainly not a pretty solution... but we haven't come up with
anything else yet.... the only step I can see possibly simplifying is on
outbound faxes Hylafax can possibly be bypassed and have t38modem talk
directly to IAXmodem.

	 

	--

	Matt

	 

	 

	 

	From: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of arkda
	Sent: Sunday, December 09, 2007 11:59 PM
	To: Asterisk Users Mailing List - Non-Commercial Discussion
	Subject: [asterisk-users] T.38 fax solution, opinions?

	 

	Hi,
	
	I'm putting together a fax solution for my company that utilizes
T.38. I wanted to throw out my plan and get some feedback if anyone is doing
something similar or sees a blatant problem with it.
	
	We're currently rolling out SPA-942 phones for the standard desk
phone with vanilla Asterisk 1.4.15 (just upgraded it today) on the back end.
Most calls for satellite offices are handled by VoIP providers (for voice
Vitelity inbound, Gafachi outbound). These satellite offices are using a T.38
fax DID from Gafachi, passed through the Asterisk server to a Linksys 3102
ATA and then to a POTS fax machine. This all works well thus far. 
	
	Our HQ has a full voice PRI, terminated on the Asterisk server with a
TE120P. Additionally, right now they have five fax lines totally separate
from the PRI that are used for POTS fax machines.
	
	I'm thinking of porting those numbers to the PRI and purchasing a
TDM880B (comes with eight FXS modules) and routing the fax DIDs to the 880 in
Asterisk. Five of the ports would connect into a Linksys 3102 that would
speak T.38 to what would be our new fax environment (Exchange 2007 Unified
Messaging). That part isn't implemented yet, but it shouldn't be a problem.
Once it's implemented I'll probably reroute the Gafachi T.38 fax DIDs to
Exchange through Asterisk (with sipX in there somewhere).
	
	The part(s) I'm unsure about is the TDM880B. I haven't used a FXS
card with Asterisk, and I certainly haven't used a fax machine on that FXS.
Additionally, I'm not 100% sure the 3102 will talk directly to Exchange UM
yet, but that's something I can figure out myself soon; I'm just not sure
about spending the cash for a TDM880B without knowing someone has thrown
faxes through it from a PRI terminated on the same box from a separate card. 
	
	Anyway, thoughts, criticisms, insults and stinging barbs all welcome.

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