Re: [hylafax-users] COMREC invalid response received PSTN <--> Asterisk <--> Hylafax

[Joseph <syscon@xxxxxxxxxxxxx>]

> >Can somebody point me in a right direction.
> >I'm running Hylafax with Asterisk:
> >PSTN <--> Asterisk <--> Hylafax
> >
> >I'm using an external "MultiTech Modem"
> >Sending faxes works flawlessly, though receiving faxes works 90% of the
> >time.
> >  
> >
> 
> You're going to have lots of trouble with this configuration because to 
> accomplish this configuration you're either using a TDM card and 
> connecting the modem to that, or you're connecting the modem to an ATA 
> device (such as a Sipura SP-2000).  The TDM card drivers have known 
> problems for faxing, and in using an ATA device you're converting the 
> fax audio stream to a VoIP stream, and you can run into problems that way.

It seems to me you have experimented a bit with this setup.
I'm using Sipura SPA-3000.

> That said, I sometimes test HylaFAX with an analog modem connected to an 
> ATA, and generally speaking it works tolerably well, but there are far 
> more errors with it than if I were to plug the modem directly into a 
> PSTN line.

When I has using Hylafax connected directly to PSTN line I never had a
problem.
Sometime I a customer from Mexico would have to resend it twice.
But with Asterisk in between it works reasonably well as you stated.
Though, the faxes from customer in Mexico will not go through.  I don't
know why, their fax setting or something else is causing the problem.
I've been receiving faxes from Europe Asia with Asterisk in the middle
and it works OK (most of the time).

> Your best chance for success this way would be to use latest HylaFAX CVS 
> HEAD and to switch to Class 1.

I'll try to switch to Class 1 first as you suggest.
I know the best way is to connect Hylafax directly to PSTN line but with
Asterisk capability and NVBackgroundDetect
http://www.voip-info.org/tiki-index.php?page=NVBackgroundDetect

It is hard to resist.  NVBackgroundDetect gives me a chance to utilize
the fax line for incoming and outgoing voice call.  For me like most
other small businesses this Line is just sitting idle (getting two or
three faxes a day).  
So the solution with Asterisk is not perfect yet but tolerable.  

> The other option with Asterisk, currently, to get reliable faxing is to 
> ensure that the PSTN line is digital and that Asterisk never converts it 
> to an analog signal.  So the PSTN line needs to be T1/E1 coming into 
> Asterisk on a TE405P (for example), back out on another T1/E1 port, and 
> then into another digital device, such as a T1 channel bank; then you 
> plug the analog modems into that.

T1/E1 might work, but it is over-kill for me.

> Someday, when Asterisk supports T.38 (and as T.38 employs T.30 protocol 
> I must also say that when it supports T.38 as *reliably* as HylaFAX 
> employs T.30), then you could plug your modem into an ATA that supports 
> T.38 and use T.38 to avoid VoIP-streaming the fax audio signal.

I think the new Sipura 2100 supports T.38

-- 
#Joseph

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