[Asterisk-Users] Fax with Asterisk and Sipura 2100

[Joash Herbrink]

You could use a cisco ata 186.
There aren't very cheap, but I have made them work on several of my
customer sites with faxes.

The ata just registers to the * server as a SIP endpoint.

Also, echo cancelling and other "intelligent" things are bad when
dealing with faxes and modems.

Just use the cisco ATA (or any simple vegastream ATA device) to send /
receive faxes.

Codec should always be G.711 and no CNG or VAD or echo canceling should
be used, fax machines take care of that themselves.

(Contact me of list if you any of the mentioned devices)

Joash
joash at kahuna.nl


-----Original Message-----
From: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Remco
Barende
Sent: Thursday, January 05, 2006 4:42 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [Asterisk-Users] Fax with Asterisk and Sipura 2100

I tried to get it working for a very long time (over a year) with every 
possible set of config parameters I could find both for * as well as for

the Sipura's. Echo cancelling etc. etc. all changed but still problems.

I tried to get it working on an * box with a BRI line.

Finally I have given up and attached a traditional ISDN -> Analog (A/B) 
converter to the ISDN line for the faxing bit next to Asterisk.

I have yet to find a similar solution for faxing with a PRI, I'm afraid
it 
will be impossible because as far as I know it's not possible to hook up

some sort of A/B adapter next to the * box on one pri line.

I think it can work if your fax machines are capable of capping fax
tx/rx 
speeds to 9600 baud maximum without error correction. However it seems 
that not a single producer of FAX equipment (be it modems, all-in-one 
devices or even dedicated fax machines) offer such an option. HP doesn't

seem very interested in capping the fax speeds for their all-in-one 
thingies.

All fax products keep trying to transmit/receive at higher speeds 
after which the fax will fail completely or after the second page.

Maybe there is a solution coming for PRI faxing. Junghanns informed me 
some time ago that they were working on a PRI card with a possibility to

sync the clock to other cards.

If this works in theory you could use a Junghanns PRI card and a
Junghanns 
BRI card, sync the clocks and keep the path fully digital without lost 
frames. On their website however they only mention the possibility to 
interconnect the PRI cards, not (yet?) PRI <-> BRI.



On Thu, 5 Jan 2006, Darrell Long wrote:

> I know the subject of faxing has been covered in some detail, but I
was 
> wondering if anyone has a hardware configuration similar to ours that
has 
> faxes working successfully and would be willing to share any 
> settings/insight.
>
> We are unable to fax reliably with a Sipura 2100 connected to
Asterisk. We do 
> not route calls over the Internet and our network has very low
latency. The 
> Asterisk servers connect to Cisco Routers that have PRIs from various 
> carriers. We have all the recommended settings in the Sipura ATA, with
Echo 
> Cancellation and Silence Suppression off, uLaw only for the codec,
etc.
>
> While I realize that no faxes going through passthrough like this will
work 
> 100% of the time, we currently have a less than 40% success rate with
inbound 
> faxes being the worst.
>
> Any insight anyone has would be greatly appreciated!
>
> Best Regards,
>
>
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