Order summary

Loading Cart

Norton McAfee Moneyback
Home Blog How are SIM Cards, Carriers & Mobile Numbers Related?

How are SIM Cards, Carriers & Mobile Numbers Related?

sim card carrier networks phone numbersTechnology changes every single day and it has been improving without stopping during the last years. Sometimes we wonder many technological things about our cell phone, tablet or any other device, but nobody can explain to us.

We search on the Internet trying to find an answer and understand all the information we read on different pages. Sadly, we usually do not comprehend what we find in those websites and we keep the same doubts for more and more time.

Here at SimOptions, we will do our best to make it more simple and understandable for you. In this way, you will learn how the technology works nowadays and you can also share what you learn here with your friends and family.

Today we will be talking a bit more about SIM cards and how they are related with cell phone carrier your and mobile number. If you already read some of our previous articles like The Ultimate Guide to SIM Cards, maybe you have an idea about this topic.

But we would like to share more information about it, so read more and discover how these three elements work together.


What is a SIM Card?

We need to start talking about SIM cards and giving you the most important information and details about this topic. So let’s start explaining that SIM stands for Subscriber Identity Module.

This piece of plastic stores data such as your International Mobile Subscriber Identity (IMSI) number, your authentication key -which used to identify and authenticate subscribers-, your contact list and -sometimes- your text messages. Depending on your type of SIM, all this information can be stored in SIM cards with 32 to 256 KB of memory.

There are at least three types of SIM cards: standard SIMs (25x15mm), micro SIMs (15x12mm) and nano SIMs (12.3×8.8mm). There are 3-in-1 SIM cards that come in three sizes for you to cut the SIM according to what your mobile phone needs. You need to make sure your cell phone is unlocked so you can use it with different SIM cards and carrier networks.

But not all mobile phones need SIM cards. Only GSM phones use these chips. But CDMA phones do not use SIM card, they store phone number and the rest of your information in the device itself. This means those CDMA phones cannot be used with a different mobile network unless it is an unlocked mobile phone.

It is important to remember that CDMA and GSM are the two main mobile technologies nowadays. 2G, 3G, 4G, LTE, and the most recent 5G derive from these technologies. Although they have some characteristics in common, they differ in connection speed, phone calls qualities and of course, signal reception.

Users around the word prefer GSM phones mainly because they use SIM cards, so it is easier to change your mobile phone and keep your mobile number, contacts, phone plan and some other things stored in your chip.

This cannot be done with CDMA phones. As we already explained before, they do not use SIM cards so it is very difficult to transfer between carriers without having authorization.

The comparison between CDMA and GSM technology is a very extensive topic that we have covered already in a separate article. We invite you to check out CDMA vs GSM article – What Is The Difference to learn much more information about it.  

What is a Carrier Network?

A carrier network is a single network or a group of networks that provides connectivity to large areas such as towns or cities. Telecommunication providers use these networks to share out large amounts of bandwidth over long distances.

On the other hand, mobile networks are compounds webs of different cell phone tower zones that are connected to each other. Those cell towers exchange different packets of signals that include phone calls, text messages, and mobile data. Finally, these signals are taken to different mobile devices such as mobile phones, tablets, etc.

Based on all this information that we have explained to you, there are mobile network providers. We are sure you already know popular telecommunication providers like Sprint, T-Mobile, AT & T, Verizon, and US Cellular.

These companies sometimes provide you SIM cards (in the case of Sprint and T-Mobile) or just CDMA cell phones with all the necessary information included (AT & T, Verizon, and US Cellular).

These providers give you different phone plans that will allow you to make phone calls, send text messages and browse on the internet. Or you can also choose among different data plans that are very common among travelers. Phone plans can be prepaid (when you paid and then you start enjoying the plan benefits) or postpaid (which is discount from your credit card at the end of the month).  

SIM Cards, Carriers and Mobile Numbers: How Are They Related?

Now it is time to relate all the previous information and try to make clear how the elements already explained are related to each other. Do not worry; do not feel bad if you do not understand everything so fast. The truth is that if you do not know what we described before, it is not that simple to comprehend how everything works.

SIM cards are exclusive, so their information is unique. What does that mean? The mobile number and all the stored data in each SIM card cannot be copied or duplicated. Remember that SIM stands for Subscriber Identity Module, so once you insert it in your cell phone; it is your phone’s I.D.

Your mobile network (the one where you bought your SIM card) assigns you a mobile number that cannot be changed to another SIM card that is not from the same provider. Since your SIM (with your mobile number) is what identifies you, the carrier authorizes your provider or mobile network to make phone calls, send text messages or browse on the internet using your information.

We have to admit that his topic can be kind of difficult to understand at the beginning. But once you get familiar with the most important terms, you get to understand what it is all about. Hopefully, this article was very useful so you can explain to others how SIM cards, carriers, and mobile numbers are related to each other.