[asterisk-users] alarm POTS lines

[Jeff LaCoursiere]

On Sat, 4 Dec 2010, Lee Howard wrote:

> 
> I can't pretend to know what an alarm system needs out of a modem, but as far 
> as iaxmodem acquiring data-modem capabilities that part is already 
> developing.  IAXmodem inherits its DSP capabilities from spandsp, and you can 
> see on the spandsp that certain modem types are already available in the 
> newer spandsp snapshots.  That doesn't mean that you can expect iaxmodem or 
> spandsp to work for you anytime soon out-of-the box, but know that eventually 
> you'll see this happen.
>

I did notice that he based his stuff on a newer spandsp, and that his app is 
actually functional to a point, though it is based on jack audio which I 
really don't need.  So it doesn't seem far off at all.  In fact it seems that 
it should be possible to take the functional parts from his work and merge it 
into iaxmodem.  Not too far beyond my own capabilities, but for lack of time :)

>> So is there anyone out there with the DSP skills to do the "iaxmodem-like" 
>> part of what I describe above?  Would a bounty raise any interest?
> 
> As I said before, I think the work is already being done.  And for what it's 
> worth, the monthly $30 or $40 summed over years is a petty amount compared to 
> the necessary development cost of the kinds of technologies you're 
> discussing.  You'll gladly pay $40 monthly for life than need to pay $100K to 
> develop this stuff.

Ah, but it is not for me personally, it is for the ~20,000 residents of the US 
Virgin Islands that currently pay $40/month for a POTS line just for their 
alarm monitoring.  As far as the reliability of POTS lines - in our area, that 
is exactly the problem.  The ancient copper pairs are rusting in our salt air 
and haven't been replaced in decades, and the phone company is dealing with 
bankruptcy, so won't be addressing it anytime soon.  Dead lines are a common 
occurance, and I am willing to bet that many of the alarm panels are at this 
moment unable to place calls and the owner doesn't even know.

Regardless the solution would also be good for non-emergency equipment like 
ATMs, postage stamp meters, CC machines, etc.  Not that the "product" has a ten 
year life span or anything, but what does these days?

Thanks everyone for the comments - I was unaware of the DTMF methods used by 
some panels, and may start running some tests in our lab.

I'll post back to the list if we get anything working reliably.

Cheers,


-- 

Jeff LaCoursiere
SunFone