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What is a SIM card?

What is a SIM card?

Sep 05, 2020

What it does, how it works and why your phone needs one?

Although smartphone makers around the world spend boatloads of dollars on making their devices feel different and unique, it’s rather ironic that all of them share a single component that’s critical to making them work.

That component is commonly known as a SIM card, even though there are a variety of different versions. And that SIM, is critical for smartphone use. Without a SIM card, your phone simply cannot connect to your wireless carrier’s cellular network. And if you have a phone that supports multiple SIM cards, you can connect to multiple networks or have multiple lines on one device.

Want to dig a little deeper into SIM cards? We can help you learn more about what a SIM card is and why it matters.

What Is a SIM card?

A SIM card is the critical component in your phone that allows you to connect to a carrier network to make calls, send text messages, etc.

SIM stands for Subscriber Identity Module. And as its name suggests, carriers use SIM cards to identify you and your activity on their network.

sim card network

Interestingly, SIM cards were developed in 1991, and although their sizes have changed, their functionality has stayed the same. Based on a SIM card, carriers can identify what country you’re in, what network you’re connecting to, and your SIM card ID, which identifies you on the network.

SIM cards are installed in all phones across GSM and CDMA,WCDMA,LTE and in coming 5G networks generation.

Do SIM cards work on any carrier network?

Basically in the whole world there are many different operators in different places of countries, that is to say there are hundreds of thousand of carrier networks, for each kind of sim card theorily can only support that local operator telecome,which to say the local operator must offer data like KI,IMSI,ICCID etc to card manufacturer and get card programmed before useage.

What kinds of SIM cards are there?

There are a variety of SIM cards that could be used on carrier networks, including the Full SIM, Mini SIM, and Micro SIM,normally we also call it 2FF,3FF,4FF sim card.There are also Embedded SIMs and newer eSIMs.

The main difference between those SIMs is size. For instance, the Full SIM measures about 3.3 x 2.1 inches. The Mini SIM is decidedly smaller at 1 x 0.6 inches. The Micro SIM is even smaller at 0.6 x 0.5 inches, and the Embedded SIM is the smallest of all of them at 0.5 x 0.3 inches. The eSIM, which we’ll discuss below, is a software SIM that doesn’t require a card.

SIM card sizes differences matter greatly to device makers. The smaller the SIM, the less room it takes up in increasingly thin smartphones.

We should also note that a Mini SIM can be converted into a Micro SIM by cutting the plastic in the larger Mini SIM. You’ll find some carriers do that when you upgrade an older phone.

How does a SIM card work?

SIM card functionality is a pretty simple process. The card is essentially placed into a phone where it communicates with your carrier network. It tells the carrier who you are and where you are, and identifies whether it can operate on the network. If everything checks out, you have a fully functioning smartphone.

Remove the SIM card from your phone, however, and you’ll find that your device is little more than an expensive brick. Absent a SIM card, you just can’t place calls or do anything on the network other than make emergency calls. (That’s also true if the SIM card in your phone phone hasn’t been activated.

A SIM cards unique identifier also gives carriers some control over users who dont pay their bills. A carrier can turn off service, so that even if the SIM card is in the device, a phone wont work.

Can I easily get a SIM card?

You bet. In fact, every phone today comes with the properly sized SIM card in it. But if you need a new SIM card, its as simple as going to your carrier and asking for a replacement. Theyll activate the SIM and ensure everything works properly before you walk out the store.

What is Dual SIM and why does it matter?

Dual SIM technology is typically only found in higher-end devices, but its an important feature that brings significant value to smartphone users.

With Dual SIM, you can insert two SIM cards into your device at the same time, allowing you to have two numbers on one network or two numbers on different networks. Its especially handy for business users who want to have one line for personal use and another for business use. Dual SIM can also come in handy for world travelers who might use one network connection for domestic use and another for international travel.

dual sim cards

Mostly importantly, our company Greeso can supply you Blank sim card,no matter GSM,WCDMA,CDMA,LTE,NFC cards or even multi combi cards,also we can program and print on it based on your requirement, if you have interest and request, welcome to send us details:

Email: and whatsapp: +86-18002561761

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