UC500 FXO Disconnect Issues

[Steven DiStefano]

Please feel free to edit this document with PSTN Informatoin:

If you are receiving outside PSTN call through FXO ports, and the phone keeps on ringing even when the  PSTN user releases

This problem is known as “FXO disconnect”. The following link describes the  problem and the available tools in IOS to mitigate it:
http://www.cisco.com/en/US/tech/tk652/tk653/technologies_tech_note09186a00800ae2d1.shtml