asterisk users - Feb 2009 - Slow hangup - Australia - analog - incoming calls

I have had to install a TDM800 in a site, as the telco has held off
installing ISDN indefinitely..

It's all fine except for the fact that it takes ages to hang up the line
(6 or more rings), and sometimes doesn't even bother. This is only on
incoming calls - outgoing calls work perfectly.

Is there any good tricks for a fast and accurate hangup detect in this
situation?

'callprogress=yes' helped but gave us random hangups!

Changing 'busycount' didn't help, and the fact that 1 call in 8
doesn't
hang up at all.

Is polarity reversal the only way to go?


PaulH