How SIM Cards Actually Work


You most likely use it every day, yet if someone
asked you how it works, you’d have a hard time explaining it. I’m not talking about
Physics here, it’s all about your SIM card, that little chip in your phone. So let’s
figure it out! When was it invented? First of all, have you ever wondered what
SIM stands for? It actually means subscriber identity module or subscriber identification module.
The first SIM card in the world was developed in 1991 by the German company Giesecke & Devrient.
They sold 300 SIM cards to Radiolinja, a Finnish wireless network operator. In 1992, they sold
the first GSM mobile phone with a SIM card; it was a Nokia 1101. Today, it’s hard to
find a person who’s never used a SIM card – over 7 billion gadgets around the world
use them to make calls, send SMS and surf the web. Experts predict this number is going
to grow to 20 billion in the near future. The European Telecommunications Standards
Institute (ETSI) still holds the most SIM patents, but other private phone companies
also have some important patents thanks to which SIMs work. The largest manufacturer
of SIM cards in the world is the Gemalto company, with headquarters in Amsterdam and 15,000
employees. They’re now working towards the mass production of SIMs for 5G networks. The
first SIM cards cost more than one dollar each to manufacture. Today, they’re basically
worth a few cents apiece. But that price doesn’t cover design, development, inserting chips
into plastic cards and shipping them. Why do I need a SIM card? A SIM card has unique identification information
on it, like what mobile network it belongs to. It’s called an IMSI -International Mobile
Subscriber Identity. This unique ID connects your phone number with your gadget. When someone
is dialing your number, the call will go to the exact phone you have at the moment. SIM
also has its own memory. Even though it’s really small – just 64 kilobytes – it
can store around 250 contacts and some SMS. By the way, the same memory was in the Apollo
Guidance Computer used for the first Moon landings. If your SIM card is mobile, meaning you can
remove it and put it back into your phone yourself, you can also use it on different
phones. This comes in handy when your own gadget’s battery is dead, and you desperately
need to make a phone call from your number. Can my phone work without a SIM card? Technically it can, as a camera, or a device
that connects you to Wi-Fi, but not as a phone to make calls or text someone. For the absolute
majority of phones, a gadget without a SIM card is like a human without a brain. The
good news is, even if you seriously damaged your phone – smashed your screen or bent the
casing – you could still use the same phone number and keep your contacts. All it takes
is a SIM card transplantation. How does a SIM card work?
A SIM card basically looks like a little piece of plastic. It has an even smaller chip inside
that is its Microcontroller. It’s made out of silicone and plated with gold or other
metals to help it keep contact with the phone. The chip contains a processor, memory and
security circuits. Your mobile device reads the chip when you stick the SIM in it. It
contains the operating system for the card, can do some basic math, and stores important
information. This information is put on the chip on the production line. The most basic
types of that information are your International Mobile Subscriber Identity and a 128-bit key
called Ki (Key Identification). Those are basically your login and password in the mobile
phone world. All messages from your phone to the network are in a secret code. The key
to encrypt and decrypt messages is also stored on the SIM card. This provides communication
privacy. The SIM card chip also stores specific data, such as your card’s unique serial
number, the name of your cellular carrier, your PIN (if you’ve ever wondered what it
stands for, by the way, it’s your Personal Identification Number) to lock and unlock
the phone, PUK code from the carrier to unblock the phone and much more. Even your contacts
and last dialed numbers are there. Can someone track my location with the help
of a SIM card? This is a question of both privacy and security.
While it’s creepy to think someone can track your physical location for their purposes,
it’s good to know your phone can be found when it’s lost or stolen. And, it can also
be helpful when it concerns lost kids or elderly people, for example. So, a SIM card can help
to establish your location, but it’s only one player in the “find me” game. When
you insert a SIM in your cell phone, tablet, or even car, and turn the device on, it starts
connecting to cell towers to catch the signal. As you move around, your SIM works with the
towers nearest to you to provide the strongest signal. All these towers have known physical
locations. When phone companies or the police use their algorithms to find out how strong
the signal is from this or that tower, they can narrow down the search area significantly.
Services like “Find my phone” also use WiFi data to know a more specific location.
Of course, it’ll only work when the WiFi on your gadget is on. Add GPS information
to this, and you’ll get fairly accurate data on any gadget’s whereabouts in real
time. GPS will only be handy in this situation when you have cellular data enabled on your
plan or gadget. So if you want complete privacy, turn it off, along with WiFi, and tracking
you down using information from your SIM alone will be a challenge.
Do SIM cards break? SIM cards, like just about anything on this
planet, can get damaged or broken and don’t last forever. You’ll be the first to know
when that happens, as your phone will inform you the chip is defective. You won’t be
able to connect to your cellular provider in this case. Water is unlikely to be the
reason for that damage, though, since basically all new phones have sealed ports and jacks.
The SIMs themselves have always been waterproof. Why are SIM cards getting smaller?
The first SIM cards were around the same shape and size of a credit card. They worked fine
with the first mobile phones, but as mobile technology evolved and phones got smaller,
the SIM cards clearly needed improvement, too. Imagine fitting a credit card into an
iPhone – not the best idea, right? So fortunately, SIMs became smaller and more powerful at the
same time. First came the standard thumbnail-sized SIMs. They were standard until 2010, when
the Micro-SIM became universal. But even that SIM still had too much useless plastic. Some
people who upgraded their phones cut out the most important part with basic tools like
scissors. It was pretty risky since damaging the chip even a bit could ruin it all. In
2012, Nano-SIMs came into play, which are, in essence, just little chips with no extra
plastic around them. If you ever need to insert a newer generation SIM in an older phone,
there are special adaptors for that. The future of SIM cards
The latest iPhone models give you an idea of what all SIM cards will be like in the
future. They’ll be “eSIM”s, which means embedded SIM cards. Their size will be just
a fraction of a Nano-SIM. Forget the huge pieces of plastic and scissors you used to
cut out the chips! In fact, there’ll be no physical SIM cards whatsoever – instead,
they’ll be tiny chips on your phone’s logic board. The information on the chip will
be rewritable, so you’ll be able to change your carrier with a few easy steps. eSIMs
will be cloud-based, super secure, super fast and convenient to use. It’ll also be a win-win
situation for the manufactures: less distribution and installation costs, and better design
with more free physical space on your gadget! Losing one slot on your phone is also great
because it will ensure extra protection from water and dust getting inside. So, the new iPhones already have two SIM-cards:
one of the old school physical type and the other – an e-SIM that you can use with any
carrier you like. At what age did you get your first cell phone?
Let me know down in the comments! If you learned something new today, then give this video
a like and share it with a friend. But – hey! – don’t go anywhere just yet! We have
over 2,000 cool videos for you to check out. All you have to do is pick the left or right
video, click on it, and enjoy! Stay on the Bright Side of life!

Zane Wilson

100 Responses

  1. I'm the one in a billion that has never owned a cell phone of any type. Other than emergencies, I don't see any value in having a cell phone. If i did, my wife would call me every hour to say, "what are you doing", like she does to most of her friends.

  2. Rare to find one. Ha, I guess I'm rare. I havent used one since 2007. I have two phones and an iPod. None connected to the towers. Only WiFi

  3. its great to know that my father bought nokia in early 90's since i opened my eyes in 1994 i saw that cellphone in their hands 🤩
    love you Dad 💗💗 Miss you everyday R.I.P 😢

  4. i got my first cellphone after my dad died in 2006
    mom bought me a nokia 2310 at the age of 11 just to take care of me
    she's so caring and sensitive 💗💗always calls me to ask that where i am, yet

  5. E-sim will not allow the most useful thing with a sim, which is to put it in another phone to make a call from it right away

  6. I had an iPhone 3GS when I was 14, it was the best iPhone I’ve had.. until I got the XS Max lol. I’m still using the same phone number since 2011.

  7. i am not able keep listening . Is this made with intention for toddler? There no description of how SIM card functions . Just Terms coming with technological bible

  8. I was 10 when I had my first phone. I think it was one of Sony Ericsson’s first colored screen phones, the T610. I loved it 🙂

  9. You can use a phone without a sim card nowadays. They are called eSIMs and it's one of the best inventions. Basically you can scan a QR code issued by a phone provider and register your services. Pixel 3a, Pixel 4, iPhone 11 have this capability.

  10. I have not succeeded a lot of times but now I make 603 bux per day! because of this fantastic site here MyEasyOnlineJobs .c o m

  11. OK, so I'm a space history geek, BUT, the Apollo Lunar Module only had a total of 22 kilobytes of memory (16k in the primary and 6k in the auxiliary backup) and it weighed a couple hundred pounds…

  12. I had to change Verizon Wireless phones and my SIM card did NOT carry any of my contacts over, I had to manually re-enter them. Thanks Verizon.

  13. My first phone was a Nokia 3410, i got it when i was 13, also year 2003.
    And yes, i remember the very first sim cards, thank God they are smaller today.

  14. don't remember the model of my first but it back before 2000 think maybe 1998, Motorola on Vodafone, old analogue brick with extendable aerial, this was before sim cards, number was embedded in the phone (no text messaging either), cost £7.50 line rental + call time so had to top up £15 every month or no service.

  15. This is pure propaganda in favor of Big Brother. They gloss over the track and trace features and make it look like the most wonderful possession to have. C'mon now sheeple. Please queue up for your sums. This is the last step before they imbed the sim card in your body.

  16. This is a hundred percent right Linus tech tips to the better video on it you can use a SIM card without having a SIM cards called ESIM Verizon iPhone 4 used and the new iPhone x uses it

  17. At 3:22 you said the microprocessor was made of silicone. That is wrong. It’s made of silicon. Silicone is a paste you seal things such as bathtubs or windows with. Silicon is the element that allows this tech to function as a semiconductor.

    Good video though. Informative

  18. Well i got my first phone (not rlly a phone) a peppa pig phone 😂😂😂 then at 6yrs old i got my Samsung j5 about you bright side 🙈🙈🙈

  19. My 82 yr old Mother just bought her 1st cell phone, She HATES IT lol, refuses to get rid of her landline. but once I installed slot games on it she wont put it down lol

  20. Satellites don't exist…all land based tech.. For sure there are some high attitude balloons and planes but you cannot go to space..no one went to the moon.. Think you better re-do this video..

  21. Lol this is untruthful. My phone doesn't require a SIM card at all. I have Data, can make calls and send and receive SMS without a SIM. My phone doesn't even take a SIM card. Alot of older phones especially thru Verizon doesn't require one.

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