Today we’re going to learn a bit about SIM cards.
Where do SIM cards come from? Should SIM cards be allowed to enter the United States? Are they taking away American Jobs? The answers is – from factories who make them, yes and no.
What is a SIM card, anyway?
The SIM (Subscriber Identity Module) card is a small piece of plastic with an integrated circuit that holds your cellular identity information and allows your phone to connect to the cellular network. SIM cards are a feature that exists only on GSM networks, as all other cellular methods (CDMA, TDMA and iDEN) have the identity built into the phone itself, bypassing the need for a SIM card.
For the end user, the SIM card is basically his number, allowing him to port his number among any GSM phone that will accept his SIM card (the phone must either be locked to his carrier, or be unlocked – meaning accept any SIM card).
SIM card sizes
* SIM card (aka “full SIM”) – this is the big card, which holds either the MiniSIM or the MicroSIM inside of it. The full SIM is almost never used for phones, (no modern phone is big enough to use it). You detach the MiniSIM or the MicroSIM from the full SIM and insert into your phone. Size: 3.37 in. (L) x 2.25 in. (W) x 0.029 (T)
* MiniSIM card (aka “SIM”) – this is the traditional SIM that has been around for the last decade and a half. Fits 90+% of the models currently on the market. Size : 0.98 in. (L) x 0.59 in. (W) x 0.029 (T)
* MicroSIM card (aka “MicroSIM”) – This is the newest type of SIM card. Mostly used by Apple since launching its iPad(1) and iPhone 4. You can turn your MiniSIM into a MicroSIM by cutting in (by using a cutter or with scissors). You can also turn your MicroSIM into a MiniSIM by buying an adapter. Size: 0.59 in. (L) x 0.47 in. (W) x 0.029 (T)
Most carriers these days sell mobile devices on top of their other cellular offerings (voice, data and additional services). These devices have a few purposes besides calls – customer loyalty and satisfaction, increasing revenue from each user by embedding the carrier’s services etc.
One way for the carrier to make sure their devices (which are often subsidized) are used only on their home network is locking. The carrier would essentially lock the phone through software/hardware means to be unable to accept any other SIM card that is not the carrier’s. For the user, this makes it harder to switch to a different carrier (as you have to buy a new device), harder to travel around the world (as are unable to use different SIM cards that might lower your costs), and make it harder to sell the device later on (as you have to sell the device to people who already use your carrier).
The obvious solution is unlocking the device. Sounds simple enough, but as carriers will not benefit from unlocking their devices, they might be unwilling to do so. Often you can be able to unlock your phone through local phone shops, though not all devices can be unlocked by external means as some devices have high-level hardware and software security to protect them against such actions.
Our advice is if you’re able to unlock your device, we suggest doing so – you never know when you might need to pop-in a different SIM card.