Gadgetory

back in the good old days telephones had physical wires linking one end to another this was regardless of whether or not you were making a call across the continent or just using a couple tin cans attached to a string whenever you've dialed a number your phone company could wrote your call exactly where it needed to go using said cables but in this brave new world of not only phone calls but vines and snapchats and other stuff that the kids are doing being blasted out from cell towers everywhere these signals have to know where they're going every time this is where SIM cards come in and despite the name SIM cards isn't a new casino building game from Maxis although that would actually be pretty sweet sim stands for subscriber identity module which gives a pretty big hint as to what it does it identifies what mobile phone subscriber is using a particular iPhone galaxy or Windows Phone if that's your thing for whatever reason and although SIM cards are quite low capacity with many of them holding well under a megabyte of data the small amount of information that they do hold is extremely important if you want your phone to be of any use when you don't have a Wi-Fi signal SIM cards store a 64-bit number that serves as a unique identifier and although that only takes up 8 bytes of storage there are over 9 quintillion unique numbers that can be stored in this way on a SIM card so this method should work no matter how many people sign up for Verizon when you turn on your phone and first connect to the cell network your phone will pass your sim cards ID number along with an authentication key also found on the SIM card to your cell phone provider your provider then generates a random number and uses the key to spit out a response number at the same time that random number is sent back to your phone and the same calculation is done with the authentication key to generate another response number if the two numbers match your provider will recognize this and connect your phone to the network both ensuring that it's actually you that's connected to keep your data safe and to see who you are so your provider and block access if you haven't been paying your bills because you've been blowing all of your money on freemium games but other than just identifying information SIM cards can also store phonebook information and although that might seem like a dated concept in an age where phones can store almost anything you can think of on separate internal memory or expansion cards this was important when things like flip phones were more popular so you wouldn't lose all of your contact info when you upgrade it or if you're not storing your phonebook with a Google or Apple cloud service if you are moving cards between phones just make sure that they're the same size as there are different sim form factors and that your new phone even has a SIM card slot at all some phones especially in the US have their authentication information on built-in internal memory instead of course while SIM cards are quite useful when you want to switch phones this isn't always possible because of something called sim locking you see phones you get from a major carrier with a service contract are often locked meaning they'll only work on that carriers network service providers do this so they can subsidize the cost of the phone allowing you to get higher-end equipment for a much lower price because they know they'll be getting money from you for a certain time because of your subscription contract but the good news is that some carriers nowadays have stopped sim locking while many others will give you an unlock code once your contract ends so that you can put your phone on another network in fact the u.s. passed a law in 2014 making it legal to unlock your own phone since before that it was technically considered circumventing a copyright safeguard hmm Squarespace the simple powerful beautiful 24/7 supported tool to build websites on your own it's only $8 a month and you get a free domain if you by Squarespace for a year it has that responsive design stuff that we always talk about so it looks great on a number of different devices in a number of different sizes as a commerce module so that every website has comes with functionality in order to people buy your stuff if you want to do that and speaking of buying your stuff they have new annelid tools for online stores find out where your traffic is coming from order volume how many visits result in purchases and lots more so you can keep making that sweet sweet paper start a trial with no credit card required and start building your website today when you decide to sign up for Squarespace make sure to use offer code Lynas and get 10% off your first purchase alright guys thanks for watching if you want to see more cellphone related stuff let us know in the comments down below and John we'll get right to it if you want to see other fun things click up here to check out channel super fun if you like the video like it if you just like to dislike it don't forget to get subscribed that's helpful because then you see all the stuff although if you go to the Linus tech tips YouTube page and click videos I think actually like the first thing you see is a tech quickie videos but I don't know I could be wrong you could also check that to verify if I'm wrong or not by going to Linus tech tips channel maybe watching video 2 while you're there anyways SIM card joke what oh that was funny anyways I don't know if you heard it bye