Re: [hylafax-users] Fax Extension Numbers

["Jay R. Ashworth" <jra@baylink.com>]

On Thu, Feb 15, 2001 at 11:38:02AM -0500, Christopher A. Seward Sr. wrote:
> One of the commercial packages we demo'd, FAXmaker (www.faxmaker.com)
> claims 100% success when doing DTMF routing, assuming that the person
> sending the fax uses the correct number and that the extension being
> dialed is listed in a database.

Hmmm...

> Here's a snippit from their site:
>
> -DTMF routing
> -Fax routing based on DTMF
> -
> -DTMF routing - this method requires the caller to enter an extension
> -number when sending a fax. Alternatively, if your PBX has excess
> -extension lines, you could program your PBX to pass the DTMF number
> -automatically.

> -Requirements:
> -
> -A ZyXEL or Rockwell voice modem (check for compatibility with
> -GFI) User must input DTMF number. If PBX is used, the network
> -administrator must have advanced technical telecommunications
> -knowledge to operate and program -the PBX.

> -Recommended environment
> -
> -Only in specific environments where a special PBX is available or
> -where one can explain to the callers (i.e. the senders of the fax)
> -how to input the DTMF number

"where one can explain to the callers" is the key phrase here.  This
will only work in a *non* PBX environment if the human (or worse, fax
machine) at the sending end *knows when the receiving modem is
listening* -- and there are protocol timeout issues to be dealt with at
the receiving end as well.

If your fax modem *is* behind a PBX which can fake DID (actually DNIS
these days) digits, you might get away with it more easily; PBX's can
dial *really* fast.

> Forgive my newbie-ness if I'm mistaken about this, but there has to be
> some way to do this. Thanks for the faxgetty tip. I'll dig into the
> docs on it.

But even if you can hack faxgetty to deal with this, you'll have to do
some tuning about the number of commas (pauses) that a sender would
have to include to get the burst of DID tones in the right place,
timing-wise with respect to the receiver.

Can any of the protocol gurus comment on how much slack there is
between 'faxgetty answers phone' and '[something] gives up because it
hasn't heard a carrier from the other end yet'?

You know, come to think of it, the *real* problem is going to be
getting the receiving modem *not* to hear CNG tone, and automagically
*answer* the incoming call before listening for the DTMF tones, this
might require originally answering with ATO so that the tones could be
interpreted, and then re-answering with ATA... and I don't know that
you can do that without ATHing in the middle... which may drop calls on
some lines or modems.

You begin to see how ugly this is as a hack.

I'd really love to know if anyone's actually *seeing* 100% with that
package.

Cheers
-- jra
-- 
Jay R. Ashworth                                                jra@baylink.com
Member of the Technical Staff     Baylink
The Suncoast Freenet         The Things I Think
Tampa Bay, Florida        http://baylink.pitas.com             +1 727 804 5015


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