Asterisk does not detect hang up from pstn

kindly i need to solve problem in FXO,
when i make phone call and from land line to voip extension and hangup the line the voip extension still give me alarm that there is phone call,
please i need to hangup the line in voip extension after i make hangup in land line.

thanks

What type of disconnect supervision does your service provider use on the type of line you are using?

What form of disconnect supervision have you configured in chan_dahdi.conf?

use callprogress=yes in your dahdi configuration.

The options he should be looking at are:

busydetect
and
hanguppolarityswitch

Although these depend on characteristics of the service provider.