[Asterisk-Users] Fax with Asterisk and Sipura 2100

[Remco Barende]

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,
>
>