Ask LH: Why Do We Still Have SIM Cards?

Dear Lifehacker, A friend of mine recently acquired a new phone and had to get a new SIM in the right size. That made me wonder: why do we still use SIM cards? American CDMA phones are SIM-less, so are there any specific reasons why SIM cards are still needed here? Thanks, Had My Fill Of SIMs

Picture: Simon Yeo

Dear HMFOS,

It is true that many US phones that use the CDMA network don't utilise a SIM -- the phone connectivity is programmed directly into the phone. This would be theoretically possible with other network types -- your phone doesn't care whether it reads network details from a card or the phone's own memory. However, it hasn't generally been the approach in the Australian market, and we think that's a good thing.

While it's annoying if you switch from one phone to another and suddenly discover you need a micro- or nano-SIM, being able to swap your SIM means it's much easier to acquire an additional SIM if you travel overseas, or to switch from one provider to another if you decide that prepaid is a better deal. If you have a phone which doesn't have a SIM slot at all (as some US CDMA models do), then that simply isn't possible. You're stuck with the network who supplied the phone, or at best switching to another network which also offers SIM-free access. Why limit your choice in that way?

The lesson here is two-fold: buying a second-hand phone from a US seller is risky, and being able to swap SIM cards is useful. On modern smartphones, you'll usually be able to do this without requiring an unlock code or other details from your provider -- but it does pay to check before you head overseas, especially if you have an older phone that was purchased on contract.

Cheers Lifehacker

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Comments

    Let's hope that nonsense stays out of Australia..!

      Telstra used to have CDMA in Oz - my first phone when I moved here was CDMA (and SIM-less) as it had by far the best coverage outside of cities back then and I was travelling in remote Australia solo and self-propelled.

    There's this place I seen on t.v. where people get fed and housed for free, and all they do is work out all day. I think they call it a jail. How do we get into one?

      As I was reading this I first thought "The Biggest Loser" which kinda fits the description pretty well too

    Removing the need for a SIM card does not necessarily exclude you from changing carriers easily. The current setup with CDMA does, but there's no reason it has to be that way for a sim replacement.

    A future system could be as simple as having a list of available networks/providers pop up and it asking your for a username and password.

    If we move to an entirely data-only model, which seems to be where we'll end up in the not-to-distant future, the need for SIM cards drops even more, selecting your network and providing a username and password could allow you access to a variety of different network types, Wi-Fi in urban and city locations, then going out to 3/4G in rural locations, hell there may even be more wider reaching technologies developed to allow access in more remote locations (new types of satellites for the NBNv3 which can also be easily used for Mobile purposes, for example).

    So, I think in the future we will see a world without SIM cards.

      In that case, you would have to set up some central authority and register your details with them so you can he charged, or have your details with all the providers etc. Not quite that simple.

        Why would you need a central authority? The network you wish to connect to would have you information registered if you had an account with them. If you, for example, tried to connect to Vodafone with a Telstra account, it just wouldn't work, as you wouldn't have an account with Vodafone.

          Yes, either have an a account with each one or a central one that the providers bill you from. That way you sign up once and switch between them freely or whatever.

            Only if you want to switch accounts freely. In reality though you wouldn't need any more than 1 account for most of the time. You wouldn't need to switch between Vodafone and Telstra half way through the day. You might want to change to someone else if visiting a specific area where it was beneficial.

    While it’s annoying if you switch from one phone to another and suddenly discover you need a micro- or nano-SIM, being able to swap your SIM means it’s much easier to acquire an additional SIM if you travel overseas, or to switch from one provider to another if you decide that prepaid is a better deal. If you have a phone which doesn’t have a SIM slot at all (as some US CDMA models do), then that simply isn’t possible. You’re stuck with the network who supplied the phone, or at best switching to another network which also offers SIM-free access. Why limit your choice in that way?

    If we were SIM-free in Australia, I reckon it could still work. Couldn't we "download" multiple network configurations and switch between them in the phone settings as if you were switching SIM cards? Assuming phones were no longer locked to a network.

    I like the flexibility of using a SIM card in mobile phones.

    a better Question, Why cant all SimCards be the same damn size?

      Because Apple wanted to do it their own way.

      The original ones are fairly big, all newer phones have micro sims now, except Apple. They came up with nano sim.

        Here is a list of phones that take nanosims: http://www.gsmarena.com/results.php3?sSIMTypes=3.
        You will note there's a few more than just apple.

        And jumping back to the original topic, Telstra's old CDMA network was sim free. I used it, and it was a breath of fresh air to go back to a sim-based service.

        Last edited 11/08/14 3:26 pm

    They were, but phones have been pushing to get smaller and part of that has necessitated getting rid of all the useless cardboard that holds the chip itself in place.

    I'm not sure about the newer Micro sims but the chips in the first nano sims were actually cross compatible if you had someone cut the cardboard down.

    Of course this wasn't recommended by Australian carriers, but I believe it was standard operating procedure in India and other countries with high smartphone adoption rates but no official import chain.

      I'm pretty sure they all can be cut down. I cut my sim down to micro sim size and it was fine.

        I didn't want to say for sure, for one because I always forget which is the newer and smaller one and two because I have no experience with the newer ones one way or another.

        SIMs can be cut down to Micro SIM, but SIM & Micro SIMs can't be cut down to Nano SIMs. SIM & Micro SIM are the same thickness. Nano SIMs are very slightly thinner.

          I did not know that about the nano! From pictures it looks to have the same chip but I've never seen the thickness mentioned before. I wonder if it's possible to peel off part of the plastic/board from the back.

    No one raises the point of the IMEI and IMSI numbers? Especially with all the data retention talk of the past week?

      Fine. The IMSI is the subscriber identity and is stored on the SIM card. The IMEI is the equipment identity and is part of the phone. The IMSI doesn't technically need to be stored on the card, but for a variety of histroical reasons, it is. Happy now?

        Right. And there are very valid reasons to differentiate between the two, how they are stored, and track changes to both.

        Which you don't get with the US SIM-less system.

        Which was my point. Point, not an explanation of what they are.

    Takes me back to the days of selling analogue phones.. and remembering the long sequence of *# +digits to program a new analogue phone onto the network.. I used to be able to do almost all of them from memory.. damn, makes me want my Nokia 2110i back.. sim cards certainly made the process of selling a phone much simpler..

    Why move backwards? - SIM free (CDMA) is not the future, its the past. I had a situation where i had a disagreement with my carrier, so i threw the sim away and got a new one with a different carrier, activated it in 5 mins and my number was ported in less than an hour. Without SIM cards the carrier could hold you ransom.

      I don't see why software couldn't be used to register a handset to the network. In your case instead of throwing out the losing carrier's sim card, you simply go to your new provider, sign up an account then they plug your phone in to update the network registration.

      Maybe its a security issue or something!?

        The network has to accept your phone. It's very rare in the US for a CDMA provider to accept a CDMA phone that they did not sell. If you want to use their network, they want you to buy their phone. Also no US carrier allows voice calls adn 3G data at the same time - possible on the standard, but no US carriers allow it. And CDMA doesn't support LTE. So if you want 4G on your CDMA phone, you still need a SIM card - and CDMA 3G Is very slow compared to GSM 3G.

          I'm not suggesting we move to a CDMA setup at all., Why can't a GSM network be 'sim free' or 'built in'?
          My understanding is that the whole mobile network infrastructure would need to be changed to go back to CDMA any way which is totally backward. I'm simply suggesting that instead of having to use a removable 'chip' surely in this day and age that 'chip' could be manufactured into the phone and 'programmed' by software from the carriers.
          Australian networks are very different to American. They are embracing people who 'BYO' device and go onto a sim only plan, so I can't see the carriers here having a problem with you buying a handset elsewhere and then signing up to a sim only plan.
          I can only think that there is an issue with security that would deter moving away from sim cards.

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