[Asterisk-Users] FXO Disconnect supervision

[Glen Johnson]

Does anyone have disconnect supervision working on their TDM400P or X101P 
cards (to/from the telco)?

Googling "telco disconnect supervision," I found the following description:
http://mirror.lcs.mit.edu/telecom-archives/telecom-archives/TELECOM_Digest_Online/1559.html

[cut]
Re: How Do I Get "Kewlstart" From my Phone Company?
Paul A Lee
Tue, 24 Aug 2004 16:58:16 -0400
...
It appears that "kewlstart" is just a coined name for loop signaling
with disconnect supervision. Disconnect supervision is also called
"calling party control", "forward disconnect", "open loop disconnect",
"open switch interval", "adjunct control", and perhaps other
names. What is supposed to happen is that the CO switch (or other
switch serving as the office end) will remove battery voltage from the
loop for about 250 ms within 6 seconds after the far-end party
disconnects.

As far as I can tell, most CO switches now seem to provide disconnect
supervision by default on loop-start lines. Consequently, it can be
difficult to find someone at telco who knows anything about it.
...
As for availability on residential service, just check your current
loop-start line(s) with a voltmeter and see if it drops toward zero
for about 250 ms when the far end disconnects from the call. If
there's no disconnect supervision, you'll see the voltage stay at
about 7-8 VDC when off-hook, and about 48 VDC on-hook.
[/cut]

I can hear what sounds like a battery drop on my lines when the far-end 
disconnects but asterisk doesn't seem to detect it.

Anyone have ideas.  Or experience with this?


Regards
Glen Johnson