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SIM cards are just a little piece of tech that each and every person who has ever had the privilege of owning a cellphone is incredibly familiar with. But do they know how they actually work?

Back in the day before cellphones existed, every single telephone was connected directly to the service provider using a network of cables. But this was inevitably going to die out as technology improved.

Cellphones get their signals from thousands of cell towers around the globe, but the problem is that the cell towners need to know where to send these signals to.

This is where the Subscriber Identity Models, more commonly referred to as "SIM cards", come into play.

SIM cards identify what mobile phone each subscriber uses, whether it be an Apple iPhone, Samsung Galaxy or Nokia 3310. It will send your mobile phone's unique ID number along with an authentication key to the cell provider. Once revied by the cell provider, they will generate a random key and send it back to the SIM card. Your SIM card then generates a random response key and, if these two numbers match, you will then be granted access to the network.

These generated keys and response keys are all controlled by your service provider. They can identify which data/airtime contract plan you are signed up to and provide the necessary amount of use in return.

Check out the video below by the YouTube channel: Tech Quickie on How Do SIM Cards Work?

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