[asterisk-users] UK call initiating party hangup control on analoghome lines

[Don Kelly]

The wiki had this about UK POTS:

In the UK, if you are using BT and are having problems with Asterisk not
detecting hangups when using a TDM400P, contact BT and ask what the current
"Disconnect Clear Time" setting is for your phone line. Mine was set to 100
and increasing it to 800 fixed the issue. "Disconnect Clear Time" (DCT) is
BT's name for CPC. You will need to speak to the BT Faults service--they can
check to see what your DCT/CPC is set to and reset it instantly to another
value. 

BT have two analogue line specifications: single line (BT SIN 351), and
multiline (BT SIN 352), which explain the different forward disconnect
parameters (http://www.sinet.bt.com/). These specifications state that for
single line (like most of us have), the disconnect time is between 90ms and
130ms, for multiline it is 800ms. My impression is that the rest of the
World (North America included) has a disconnect time in excess of 500ms,
this explains why the default behaviour of zaptel (Digium and Sangoma cards
alike) don't play well with single line BT phone lines for disconnect
supervision.

When ordering lines from BT - especially feature lines or business lines ask
the sales person to set lines to PABX working.

And if none of this works, it looks like the "maxsilence" parameter could
end voice mail recording and allow you to terminate the call.

  --Don

Don Kelly
PCF Corp
Real Support for your Virtual Office TM
651 842-1000
888 Don Kell(y)
651 842-1001 fax

 

-----Original Message-----
From: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Gordon
Henderson
Sent: Tuesday, September 16, 2008 3:08 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [asterisk-users] UK call initiating party hangup control on
analoghome lines

On Tue, 16 Sep 2008, Roberts Klotins wrote:

> Thanks Don,
>
> I have looked at that page and the described problem (when asterisk does
> not detect remote (calling) party hangup) is exactly the opposite to my
> case. In my case I learnt that for BT residential analog lines the
> remote caller is entitled to hold the line open indefinitely, regardless
> whether I hang up or not. So this seems to be a feature of BT rather
> than a problem with asterisk.
>
> I do not know whether there are many countries where telco setup is
> similar.

That might be worth a posting to usenet:uk.telecom ... I've a funny 
feeling this is exchange dependant and it's not the same action for all 
exchanges. I can call my home BT line, answer it, then hangup and the call 
is cleared inside 10 minutes (usually 2-3) then I can make an outgoing 
call.

I'm told that you need to tell BT that you have a PBX on the end of the 
line, but I've never done that for any analogue installation I've done.

Gordon


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