@Stewart1 wrote:
Confirm that on an incoming analogue call, Asterisk really does disconnect when the caller hangs up. Usually, the called extension would also hang up, which would cause Asterisk to disconnect the call.
I know nothing about the A200, but if your PSTN lines indicate disconnect by dropping loop current, you should configure the FXO port appropriately. Otherwise, Asterisk will have to detect the "disconnect tone" pattern sent from the central office. Settings are in indications.conf and vary by country. You may find http://www.experts-exchange.com/Networking/Telecommunications/IP_Telephony/Q_26485204.html useful.