Check out our guide for a closer look at the two popular wireless standards, CDMA and GSM. They're becoming a bit less relevant in the face of LTE, 4G, and 5G.

While GSM uses the information stored in a SIM card in order to work, CDMA, on the other hand, keeps the same type of information within the device itself.

All GSM phones and most iDEN phones require a SIM card to operate. There are certain types of phones (CDMA, TDMA, AMPS) that do not use a SIM. Instead, ...

The long and contentious battle for the exact shape of the nano-SIM / Fourth Form Factor (4FF) technically came to a close on June 1st. However, the standards body behind the decision, the ETSI ...

GSM: SIM CDMA: MEID, U-SIM. First, let’s get this out of the way: I’ve been using GSM and CDMA as blanket names for a set of standards that have changed over time.

The Verizon phone uses CDMA so there is nowhere to put a GSM SIM. But a bit of hacking allowed him to add a SIM card slot to it. Even though he’s not the one who originally found this hack ...

There are many options available if you want to control your appliances over WiFi, but how about an oven with its own SIM card and phone number? That's exactly what AGA has done with its latest ...

Unlocking a GSM device allows you to use pay-as-you-go or prepaid SIM cards from other carriers. Prepaid accounts can work out cheaper than postpaid accounts because even though the per-minute ...

While GSM phones enable you to remove the SIM card from one phone and insert it into another phone on the same carrier's network, you cannot always switch SIM cards between carriers, such as AT&T ...

By combining GSM SIM Toolkit and Class 2 SMS messages (the type sent to handsets where there's no user interaction required) the Gemalto "Facebook for SIM" doesn't require the handset to have a ...

GSM and CDMA are the two ways phones talk to cell towers. Pure GSM phones won’t work on a CDMA network, and vice versa. At home, on your home network, this isn’t an issue. When you’re ...

Having the Palm Pre on Sprint might be good for Americans driving their pick 'em up trucks down the CDMA data highway, but it doesn't do Europeans (or Palm's bottom line) any good over in the Old ...