It is also highly dependent on your location.
For example, in Australia, when the phone is not in use, I believe the remote plays a continuous series of tones down the line (that isn't heard by the consumer), where as in North America the line goes pretty much dead (but still live in terms of voltage).
When someone hangs up on you in Australia, you immediately get a busy like signal, where as in North America you either get a moment of dead silence or it returns you to a dialtone so you can make another call.
On this page http://www.nch.com.au/hardware/setup/fxo.html, NCH has listed the proper disconnect/hang-up settings for Australia, (the defaults on the device are for North America) and you can probably find more configurations online.