[Asterisk-Users] FXO Issues

[Rich Adamson]

> Experiencing some issues on my FXO lines. If a call comes in on an FXO and then get 
transferred to another FXO (say to call someones cell
> phone), those two lines will stay tied together indefinitely. This happens to us when we 
transfer an incoming call to our on call guys after
> hours and on weekends. We have installed 3 other * boxes and they do the same thing.
> 
> We use a Adit Channel bank for all incoming FXO and the other installs use multiple 1 port 
digium FXO cards or a combination of the 1 port
> and 4 port FXO cards.
> 
> Has anyone else experienced this and if so how did you fix it?

If you're using plan old pstn analog lines, put a voltmeter on the
analog line to see if you have call supervision coming from the telco.
You should see the voltmeter either dip to zero volts for about a
half second, or, voltage reverses for some short period of time.
That should occur within a few seconds after the caller hangs up.
Exactly "when" that occurs varys by central office switch manufacturer.

If you don't see any form of supervision, then you have to implement
some sort of timer, tone detection, etc. You can also talk to your
telco engineering/tech folks to see they have any options for call
supervision. (The sales office won't have a clue in most cases.)

Other choices might include changing your pstn lines from loop start
to E&M signaling, etc.