If I make a call to a mobile phone from an ISDN30 PRI line and the call is A) not answered (but no voicemail) or B) the call is rejected, is there any list anywhere of the different codes returned to the ISDN (hangupcause) For example, if I call an o2 mobile, and "reject" is pressed then I get a hangupcode 16. However, if I call a virgin mobile, and "reject" is pressed, a hangupcode of 31 is returned. Anyone know why this may be the case ? Or does anyone have a list for the mobile operators ? Many thanks Julian