Yes you can put any working Falcon sim (i***) into any Falcon phone, and it will work. The only time it becomes an issue is some of the newer features my not work or be inabled for the phone until Nextel is contacted and changes your account to match your new phone. Basic service will work without any problems unless as stated above the phone has been reported lost/stolen. You can contact Nextel or if you have a local dealer that you deal with alot and they can findout the status of the phone and you can then make your decision to send it back to the guy or not.

you should not have a problem, they use the same sim cards but I would check with nextel, it sounds like someone sold you a phone that was reported lost/stolen.

Hi everyone, i currently have a i730 and i just bought a i860 from ebay. I was told that you can just switch the 730 sim card to 860. It would work for only 2mins then i get an "Service Restriction' error. Do i have to get the 860 regestried from nextel???? i need help, feel like returning it if nothing works.