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

john at netdirect.ca john at netdirect.ca
Fri Feb 19 17:57:27 EST 2010

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 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.
564 Weber St. N. Unit 12
Waterloo, ON N2L 5C6
john at netdirect.ca
Ph: 866-883-1172
Linux Solutions / IBM Hardware
Fx: 519-883-8533

More information about the kwlug-disc mailing list