What is a SIM card?
A SIM card is a small, tiny little chip (called a card, for lack of a better term), that you can insert into some smartphones. This card holds personal data with your selected carrier, basically allowing the carrier to identify your device and then turn on/off select services based on the plan you have setup with your carrier. If removed from the smartphone, your plan — and data — cannot be accessed (and therefore the phone can only be used, limitedly, on a Wi-Fi network) until it’s put into another phone.How does it work?
A SIM card contains your personal phone plan data, such as your phone number and your service plan with whatever carrier you have. That’s the neat thing about SIM cards: that they give you some freedom when it comes to your phone. If you end up buying a new phone every now and then, and the SIM slot is the same size as on your original phone, then you’ll be able to simply insert your SIM card and use that as your primary phone, without having to get a new phone number, new data plan, and so on.Essentially, SIM cards are your personal data plan, in your hands. Since you’re paying for it, it’s a physical piece that you can use however you want to use it. Using a carrier that utilizes SIM cards in their phones will give you the ability to use a different phone for every day of the week if you decide that’s something that you want to do. No need to contact your carrier, because it’s your SIM card, and you’re essentially just moving the home of your data plan around.
Why some companies use SIM cards and others don’t
Before fully understanding what type of phone you’re buying and how SIM cards come into play, you need to know the difference between GSM carriers and CDMA carriers.GSM stands for “Global System for Mobile Communications,” while CDMA stands for “Code Division Multiple Access.” The difference between the two, in the simplest of terms, is the SIM card (for GSM networks) and the lack of a SIM card (for CDMA networks, although that’s changing). It’s worth noting that while Sprint and Verizon are considered CDMA carriers, they do offer SIMs in a limited sense on a newer LTE phones that will work just fine on any GSM network.
We’ll start by addressing GSM (Global System for Mobile Communications), first. In these phones (or phones provided by AT&T and T-Mobile), you have to keep your SIM card inserted at all times in order to use your data, as your plan is tied to your SIM card. If you want to receive calls, the SIM card must be inserted. If you want to use your available data from your chosen plan while out and about, the SIM card must be inserted. However, you can use the smartphone for apps and internet when connected to a Wi-Fi network.
As aforementioned, the neat thing about GSM phones is that you can change them just about any time you want, without having to contact your carrier, order a brand new phone from them, and so on. If you happen to work in a business where you get to frequently test new gadgets, or you just have access to a variety of different phone styles, it’s nice not having to jump through a bunch of hoops to change things up every once in awhile.
CDMA phones, as mentioned above, do not typically have SIM cards or work with SIM cards (with one exception we’ll point out in a minute). The reason for CDMA phones not requiring SIM cards is because it’s a different technology than GSM, and its radioactivity is also different. To put it simply, instead of your data plan being attached to a portable SIM card for you to use as you wish, your data plan isn’t physically in your hands, but rather your carrier’s, hence the need to contact them if you’re wanting a different phone and are also wanting your plan to carry over.
Although CDMA phones are different for a variety of reasons regarding technology, radioactivity, and all of that, there are some that are being made available with SIM cards, and typically these are for 4G LTE networks. As those networks expand, we’ll be seeing more and more of SIM cards, which overall gives the consumer more freedom with whatever data plan they have.
