[Asterisk-Users] zap to zap bridging not hanging up

[Rich Adamson]

> On Sunday 05 June 2005 12:21, Rajkumar S wrote:
> > Sorry to intrude into this thread. I have a similar problem which I
> > posted a couple of days back.
> > http://lists.digium.com/pipermail/asterisk-users/2005-June/110617.html
> 
> You shouldn't have to restart asterisk.  the soft hangup command should also 
> work.  But yes, it otherwise sounds like your provider does not provide CPD.
> 
> > Is there a way for me to check if my network provides CPD, if indeed
> > that is the problem?
> 
> Easy way is with one of those cheapass phones which have an LED which comes on 
> when the phone is in use.  If the LED goes off briefly when the remote party 
> hangs up, there's a pretty good chance you have either battery drop or 
> battery reversal CPD.
> 
> The *proper* way to see it is with a voltmeter.  your off-hook voltage should 
> be between roughly -5 and -15 Volts DC.  CPD should either disconnect the 
> battery (0V) or reverse the battery (-5-15VDC) briefly upon remote party 
> hangup.

Just to add to Andrew's comment above, the majority of US analog pstn
lines will disconnect battery for about 400 milliseconds. However,
a fair number of non-US countries either provide no disconnect supervision, 
or use some other approach (eg, tones).