[asterisk-users] alarm POTS lines

[Andrew Joakimsen]

On Thu, Dec 2, 2010 at 11:58, Jeff LaCoursiere <jeff at sunfone.com> wrote:
> we have a low-cost Atom based PBX and a "fax relay" setup locally with
> hylafax/iaxmodem to solve that issue, and it is working very well.  We
> don't however, have a solution for their alarm lines.

You would desire the entire path to be UL listed if you are doing
anything other than facilitating the phone call to the central
station. There is app_alarmreciever in Asterisk, and furthermore the
ContactID protocol is pure DTMF so that should work without issues.
But why use phone lines at all? Recently I installed a DSC T-Link
TL260GS which uses internet and GSM, there is no phone line plugged
into the alarm panel at all.

> The problem is of course that modem calls over VoIP are flaky at best.
> Even though these alarm calls are low baud rate, when we test with the
> alarm company we only pass about 30% of the time (ulaw from customer site
> to our central switch, then out a T1).  To be fair there is no QoS on
> their Internet links yet, and that certainly plays a role.

SIA format is 110 or 300 baud, ContactID is (rapid) DTMF.

-- 
Med Vennlig Hilsen,

A. Helge Joakimsen