[kwlug-disc] VOIP and Direct Detect (offtopic)

unsolicited unsolicited at swiz.ca
Fri Feb 19 23:52:20 EST 2010

John, in the case you mentioned:
- what were they using to connect the fax to asterisk? (A board, a ???)
- in your experience, did the fax work because of asterisk, or did it 
just work? i.e. With the SPA-3102 'directly connected' to unlimitel, 
should faxing also have worked, or did asterisk make something happy?

john at netdirect.ca wrote, On 02/19/2010 5:57 PM:
> kwlug-disc-bounces at kwlug.org wrote on 02/19/2010 04:54:17 PM:
>> I know this is off topic, but since there are a few VOIP experts here,
>> I am humbly requesting any advice I can get.
>> I am moving into a new house in a couple weeks and was just thrown a
>> curve-ball. I just found out that the Kitchener won't give us an
>> occupancy permit unless we have this direct detect service:
>> http://www.kitchener.ca/city_hall/departments/devtech_services/fire/
>> direct_detect/residential_monitoring.html
>> Of course, they "say" that it only works with a Bell phone line.
>> Apparently it is just a device that dials out when the smoke alarm goes
>> off. I have convinced them to let me "try" it with my voip ata.
>> I'm going to get DSL service at the house on the first, and our
>> inspection is on the second, so I need this thing to work right away or
>> problems will ensue.
>> I'm considering involving my lawyer if this delays our occupancy
>> permit, but I'd like to know if anyone here has used this system with a
>> voip ata? Any chance this will simply work?
>> note: I'm using a linksys spa-2102 with Acanac and have been using it
>> for over a year, so it's already configured correctly for phone use.
> It would depend on how the detect-direct data communications is happening.
> Typically modems and faxes don't work reliably on VoIP systems. The 
> modulation requires predictable timing that VoIP can't reliably provide. 
> Also I've read that the echo cancellation also effects the signal. I've 
> read it's possible to dial a #99 prefix or something like that on some 
> ATAs to remove echo can, but I doubt the detect-direct box will know to do 
> that.
> That said, we've had customers use faxes connected to ATAs using an 
> Asterisk box on the same LAN fairly reliably. I say "fairly" because they 
> did have some problems but we never nailed it down to the VoIP before they 
> stopped doing business. I would expect trying to fax over VoIP through the 
> Internet would fail reliably.
> If the communications relies on touch tone signals it should work as long 
> as you have the proper DTMF support configured. Some configurations like 
> to eat DTMF so careful configuration may be needed.
> It sucks that you are paying for something that your taxes should already 
> be paying for.

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