I'm a firefighter and when I jump into my gear and hit code 3 it seems to always get my girlfriend on the other line. She can listen to the entire call. If you ever find out a way to lock the phone by setting your own lock combo let me know. I know you can go in to security and set a combo there but its only a one time combo. Once you hit the combo you have to go all the way into the security program again to activate it.
Garrett