[asterisk-users] UK FXO hangup detection with a twist

[Steve Davies]

On 31/03/2008, Mike Dent <mcdent at gmail.com> wrote:
>
> On 31/03/2008, Steve Davies <davies147 at gmail.com> wrote:
> >
> > The twist? We actually have far-end hangup detection working fine, and
> > that seems to be where the problem lies for most people. Our problem
> > seems to be with requesting a hangup from our end reliably.
> >
> > If we originate the call, we can hang it up. This suggests to me that
> > the Sangoma A200D is sending the correct hangup signaling. This way
> > round, it is 100% reliable.
> >
> > If we accept a call originated elsewhere, then we cannot hang it up.
> > Only the call originator seems to be able to do that. The upshot is
> > that if asterisk hangs-up a line, and then tries to re-use it for an
> > outbound call before the remote has disconnected, we are simply
> > re-connected to the original caller, and start to play DTMF at them!
> >
> > Has anyone experienced this before? Anyone found a solution?
>
>
> People regularly use this feature to answer a call, then decide they need to
> run upstairs to speak etc, so they put
> the receiver down, go upstairs (or wherever) and pick up the handset to
> speak. It dates back many years and I  should think is designed in to the
> system in the UK. Not sure on modern exchanges how long it would take for
> the
> line to clear.
>

I do the same myself, but for PABX use, that feature must be fatal!
The line clearing time is long... I waited a couple of minutes at
least. Is it possible to turn it off (call BT and ask for a certain
feature to be enabled/disabled) or to shorten the line-clearing time
to zero? Or perhaps Asterisk is able to detect the line state or the
dialtone and act correctly to avoid re-using an open channel.

In fact, the "obvious" way to do this might be if Asterisk could set
the channel state to "hanging up" and wait for the far end signal
(loop disconnect) that the line has actually been disconnected.

This is a bit of Zaptel that I've never looked at, so I have no clue
if what I am suggesting is even slightly possible.

Steve