[asterisk-users] alarm POTS lines

[Jeff LaCoursiere]

On Thu, 2 Dec 2010, Kevin P. Fleming wrote:

> On 12/02/2010 10:58 AM, Jeff LaCoursiere wrote:
> 
>> I would love to see a DSP "modem" that could answer an asterisk channel,
>> send the data stream over TCP to some remote asterisk, which could then
>> "relay" the stream by making an outbound DSP modem call on a PSTN trunk.
>> Has anyone attempted anything like this?
> 
> Guess what? There is already a standard for this, called V.150, Modem
> over IP. It certainly would be possible to implement this sort of thing
> for Asterisk, and some small steps in that direction have been taken way
> in the past... I'd suggest doing some Google searching to see what you
> can find.

I did find an interesting thread for this in 2006 :)  I wonder if it is 
being made overly complicated, though.  I guess what I was envisioning is 
something like IAXModem that would provide a serial device... if that 
could be done, to the point where minicom or similar could actually make 
data calls via a PSTN line, then I would be very close to what I need.

I envision this:

An ATA on the local LAN with a dockstar running asterisk.  An instance on 
this machine of an "iaxmodem-like" DSP that registers as an IAX extension 
and can be called by the ATA.  A "serial proxy" daemon on that same 
machine that has the tty device open and sees the inbound call, answers 
it, then constructs a TCP session to the "serial proxy" daemon on the 
remote asterisk server.  On the remote asterisk server another instance of 
an "iaxmodem-like" DSP accepts the Hayes commands to dial out again to the 
alarm company's modem pool, and once connected starts feeding it the data 
stream coming from the alarm panel at the client's site, and sends back 
the replies in the same manner.

I really think this would work, and the daemon wouldn't be that difficult 
to write.  I don't think I have a prayer of hacking iaxmodem to do what is 
needed to emulate a modem though :)  Between the dockstar and the ATA 
(which I am already providing for dialtone anyway) it is around a $40 cost 
solution for me, and the customer gets to drop the POTS line, which is 
around a $30/month savings for them.  I'd probably just eat the added cost 
to get the customer, and could even charge some modest fee for the "alarm 
connection" that would still in the end save them money.

> 
>> So hoping this will spark some comments on the concept in general, and
>> really hoping someone has actually tackled something similar.  It could
>> open up a nice niche for even residential customers with expensive POTS
>> lines dedicated to alarm systems.
> 
> Or those customers could switch to cell-connected alarm panels (which
> are rapidly becoming less expensive and provide reliability benefits),
> or even IP-connected alarm panels. Either choice would be better in the
> long term than trying to convince an ancient alarm panel's modem to work
> over a packet network.

Totally agreed - but in our remote area of the world ancient technology will 
continue to be used for some time to come, and I need a way to sell service to 
those people that will refuse to replace any of their equipment.  I don't think 
I am alone here... and the concept would also apply to credit card processing 
machines, ATM machines, and other embedded modem devices that will probaby be 
with us for some time.  Look at fax, for example.  Wouldn't we love to tell our 
customers to dump their old fax machines for scanners and email?  Some people 
just won't until the thing catches fire or otherwise dies.

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?  A little 
more searching today turned up this:

http://www.gouloum.fr/code/sm/sm.html

Which is REALLY close to what I need...

Cheers,


-- 

Jeff LaCoursiere
SunFone