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

Jason Locklin locklin.jason at gmail.com
Sat Feb 20 21:14:50 EST 2010

john at netdirect.ca wrote:
> 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.
> John Van Ostrand
> Net Direct Inc.
> CTO, co-CEO
> 564 Weber St. N. Unit 12
> map
> Waterloo, ON N2L 5C6
> john at netdirect.ca
> Ph: 866-883-1172
> ext.5102
> Linux Solutions / IBM Hardware
> Fx: 519-883-8533
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Thanks everyone for the info. My service includes e911 and the FD don't
seem to care about the line-power issue. Yes, not all of Kitchener
requires the service, just certain locations that are a certain distance
from the fire hall. Direct detect was (apparently) a condition of the
building permit. I say apparently because we were never told.

John's comments are what I was worried about. I've never tried to use a
fax or modem over our voip connection. Acanac (our provider) says fax
will work, but I bet that if anything, the ata will be the problem point
if it doesn't work. The echo cancellation idea helps. It gave me some
ideas and I found a "Modem Line Toggle Code" for the device. I should be
able to modify the dial plan to prefix the required *99 before the FD
number (once I know what that number is).

Thanks for the pointers and I'll let you know how it goes.


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