I'm now eligible to upgrade our Alltel phones. I've narrowed down to 4 that I may choose: LG AX145 LG AX275 LG AX300 LG AX390 I just want to know which ones have field test mode & service mode (so I could program the phone/NAMS). Because thats the only kind of phone that I want. Anyone have any experience with these phone models? Which ones are the best choices with field test mode & service mode (LG menu, press 000000).