You can not individually block your extension number from appearing on your own phone, but in my humble opinion to do so is silly because you can call any other phone and ask what number you're at. However, you CAN block your extension number from showing for anyone else (internal or external) by changing the "Way to Display" parameter in Assistant for each station to No (or, optionally not block inside callers, but block outside calls from sending caller-id). I believe it is in SDAT, but I may be wrong, as well, and the AMO version of the parameter is SSTNO and setting it to Y will block the display on everything (number comes up unknown).
I do that for some of my call center phones because people like to call around the call center once they find out direct numbers, but the drawback to that is that when you place outgoing calls to people there are a number of them that will not answer the phone if it comes up as Unknown.
Don Bruechert, Voice Comm Analyst II
CareTech Solutions @ Holy Family Memorial
Manitowoc, WI, USA