GSM vs. CDMA and SIM cards

[Ron Olney]

Hello to all! I am new to this forum and a retired telecommunication consulting licensed dual master engineer. I saw the questions regarding various aliterations of SIM cards, GSM and CDMA. To make things short and not real technical, SIM cards are synonomous with GSM. CDMA does not use SIM cards but in the future they may incorporate a similar type of technology called R-UIM cards. They will not be transferable between phones. So, if your carrier uses GSM as their form of modulation of their radio signal, the phones WILL use SIM cards; if your carrier uses CDMA modulation, the phones usable on their systems DO NOT use SIM cards. As a matter of fact, for now they do not use any kind of thing like a removeabe SIM card so if you don't see a removeable card in your phone other than a micro SD or memory card, it is more than likely a CDMA phone. It will be years, possibly many years, before CDMA implements the R-UIM cards. The SIM card is a service provider reprogrammable card that carries the particular information about the specific user account ... CDMA does not use them and the phones become garbage when no longer used by the same account holder.

Best wishes,

Ron, NCE

 

[RiverOfIce]

To be honest, any removable id system will have to go away. Any future of phones will be more like cdma, non removable. Any transfer will have to be done through the phone companies. There is an insane number of reasons for this, but the main reason national security is the number one reason. Removable SIM's are a huge national security risk. Oh and welcome to the forums.

 

[Martimus]

Welcome to the Android Forums!