[asterisk-users] Distributed FAX - How to best complement asterisk ?

[Andreas van dem Helge]

On 10/10/07, Ex Vito <ex.vitorino at gmail.com> wrote:
>   Hi list,
>
>   I'm evaluating a private telephony scenario of about 20
>   locations - 300 phones, 50 FAX machines.

More than 1 PRI?

>   All other locations, small by themselves, would get SIP
>   phones managed by asterisk, since there is good IP
>   connectivity between all sites.

Private network? How good? How saturated? Could be possible to just
run ulaw if the quality is as good as your LAN

>   1. On the locations where asterisk is installed, the
>       solution is "trivial"; either by connecting FAXes
>       to FXS ports on channelbanks or by managing
>       faxes with iaxmodem + Hylafax. Probably a
>       combination of both...

Why channel banks?

>   2. On the remaining locations "we have a problem"
>   b) T.38 is the answer to FoIP
>
>   c) asterisk 1.2 does not support T.38
>
>   d) asterisk 1.4 only does T.38 passthrough, not good enough

Use a VoIP provider with t.38 for your faxes... easy solution.

>   e) CallWeaver seems to support T.38 gatewaying, although I'd
>       rather move on with asterisk so as to leverage current experience
>       and knowledge and to keep installed base with the same software.

I've been waiting for callwaver 1.2 final for a while. Tried some
betas and T38 gateway didnt work even when we put a Sangoma card in
the machine. Problem was on the SIP side.

>   [PSTN] <---PRI---> [asterisk] <---PRI---> [PRI-to-T38 GW] ...
>   ... <--SIP/T.38---> [T.38 ATA] <---FXS---> FAX machine

Too many PRI... Try:

PSTN <---PRI----> AS5300 <------SIP-----> Asterisk 1.2
PSTN <---PRI----> AS5300 <------SIP-----> Asterisk 1.4 <-----SIP----> T.38 ATA
PSTN <---PRI----> AS5300 <------SIP-----> T.38 ATA



>   4. Of course, I could use CallWeaver as a PRI-to-T.38 gateway...
>       But then again, how solid would it be ? With which ATAs ?
>       The CallWeaver website shows a very small amount of ATAs
>       confirmed to be 100% working in T.38.

There's a reason why CallWeaver is beta. As much as I'd love to
support their stuff. It's still in beta.

>   5. Would I need to have a SIP proxy between the PRI-to-T.38
>       gw and the T.38 ATAs or would they be able to talk to
>       each other directly ? (I'd say this would depend on the
>       specific equipment, but...) If that would be a requirement,
>       which way would you go, asterisk 1.4 ? Would SER forward
>       T.38 traffic ?

SER is a SIP proxy. T.38 is irrelevant to it. I'd use 1.4, your setup
seems pretty straightforward. You don't have a diverse population of
SIP phones and locations to manage.