Thanks for your reply. I agree with "You've burnt your SIM card". It's the how and why that interests me. A new SIM card from Cellular One got the RAZR working, but not the LG CU500. This time I didn't attempt to make a call with the CU500 because it didn't show any signal strength bars and I fearewd burning another SIM card. I purchased a Cingular SIM card from eBay and it shows signal strength and completed a 911 call for me. I didn't think I implied Cellular One requires a locked phone, but rather that the CU500 isn't really unlocked so it won't work with a Cellular One SIM card. When I called LG, they said the phone should work with anyones SIM card if it isn't locked. Cellular One customer care wouldn't put me through to Tier2 tech support as you suggested. I was empatically told they only work with Blackberrys. I tried getting on the ATT/Cingular forum and can't because I don't have an account with them.