[Asterisk-Users] How to Order Disconnect Supervision from SBC using Adit 600?

[Scott Stingel]

If you don't have a voltmeter to look at this, try just listening on the
line (using an analog telephone) when the far end hangs up.  You should hear
a distinct click-click on the line a second or two after they hang up.  If
you hear this, it's likely you are getting the required disconnect
supervision from the telco.  Note that many (most?) smaller private PBX's do
not drop loop current on an analog line when the far end disconnects - but
central office class switches usually do. 

It's not very scientific, but once you've heard one you can recognise it.

regards

Scott M. Stingel 
Emerging Voice Technology Inc.

Email:          scott at evtmedia.com <mailto:scott at evtmedia.com>   
URL:            www.evtmedia.com <http://www.evtmedia.com>   



-----Original Message-----
From: asterisk-users-admin at lists.digium.com
[mailto:asterisk-users-admin at lists.digium.com] On Behalf Of James Sharp
Sent: Tuesday, January 13, 2004 3:55 PM
To: asterisk-users at lists.digium.com
Subject: Re: [Asterisk-Users] How to Order Disconnect Supervision from SBC
using Adit 600?


> Can anyone help me with the term that SBC uses to refer to disconnect
> supervision?  I have an Adit 600 channel bank which has helped improve the
> disconnect detection time down to about 8 seconds. This is still causing
> some
> issues in particular with call progress enabled in * we are having a few
> disconnects while calls are in session (about 2 reported in first 5 days
> of use).
>
> I have talked both to a local phone contractor and SBC directly and no one
> seems to know what I am talking about. The phone contractor knew about the
> issue
> with other phone systems in the area but didn't know there was a way to
> fix it
> and SBC reps seem to never have heard of disconnect sup or calling party
> disconnect.

I've never seen a line from SBC that DIDN'T come with disconnect
supervision (some SBC line monkeys I know call it "battery drop
disconnect").


> The * Handbook refers to loop start with call sup as kewlstart are
> there other names for this protocol? One of the local contractors thought
> that
> SBC automatically drops line voltage on remote hangup, in which case I
> need to
> know what signalling to program into the ADIT 600's fxo channels. I also
> have
> the option of going to groundstart signalling if this would fix the
> problem, but
> it would cause some line downtime so it is not my preferred method.

Kewlstart is also an alias for battery drop disconnect.

> The Adit 600 manual lists the following options for mapping FXO ports to
> the T1 DSO.
>
> DPT = Dial Pulse Termination
> EMDW = E&M Delayed Wink start
> EMI = E&M Immediate start
> EMICPD = E&M Immediate Start with Calling Party Disconnect
> EMW = E&M Wink start
> GS = Ground Start
> GSRB = Ground Start with Reverse Battery
> LS = Loop Start
> LSCPD = Loop Start Calling Party Disconnect
> LSRB = Loop Start with Reverse Battery
> VoIP = Voice over IP (CMG only)
>
> I believe I currently have the lines set to LSCPD which improved the
> hangup
> situation, but hasn't completely fixed it.

That should be right.  If you're really interested in looking, take a
cheap voltmeter and put it across the line.  If everyone is on hook,
you'll see 48V.  If someone goes off hook, you'll see it drop to about 6V.
 If you see a quick drop to 0V when the far end hangs up, you've got
battery drop disconnect.

> I don't know if this has any relevance but I am also originating the clock
> source from the * side with Wildcard T1 card.

That's really the only way it'll work.  The channel bank can't generate
clocking.

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