I'm afraid if we kill SIM cards, the opposite will happen: your phone will be locked to one network, and switching networks means switching hardware (beyond just the sim).
I really like that while traveling I can just buy a local sim, put it in my own phone, and use it. That would only work in these wireframes if all operators would agree to support this. Which I think they won't.
This and Panmans comments were my first thought when I read that piece. I like the SIM card. When I went backpacking round the world I was able to pick up a pay as you go SIM card from a local store in any country, load it with credit and pop it in my phone and I'm all good to go. None of this sharing information from my phone business. You don't need to know my identity or payment information. I don't want the hassle of calling customer services in a country where they speak very little english because all of a sudden I have had £50 taken from my account due to some set up issue or whatever.
Anyway, as panman says, i think it will cause the opposite effect. Didn't the original GSM phones work in a similar way, with no SIM and some sort of mapping to a phone number at the carrier end? What is the likelihood that the carriers would remove the ability to change carriers, pretty high i'd say.
I find the opposite version of that quite useful too - swapping SIMs lets me change my phone hardware out independently of my carrier/phonenumber. I can (with a $2 microsim adaptor) switch between an iPhone, a Galaxy SII, and occasionally a tiny not-very-"smart"phone-but-perfectly-adequate-for-voice-and-text Huewei device. Phone calls and text messages just arrive at whatever device I've got my SIM in.
Yes, totally agree with this. There is a comment further down here that someone says they swap out their SIM into an old dumB phone when out biking since if they fall the phone is less likely break. I've had the screen crack on a phone when it was in my back pocket and I sat on something. It's also handy swapping out to those basic dumb phones when you have no recharge facilities available, like when you are at a music festival, or out camping for the weekend.
Agree with the general sentiment. The down side is something I'm waiting (hoping) for someone to fix. If I get a text message on one phone I can't get to it when I put the SIM into my other phone.
It'd be awesome if there was an operator-netural, handset-neutral, multi-platform and secure cloud-based SMS sync service.
Actually most older phones (first generation gsm-phones) stored sms (and contact-list) directly on the sim-card.
Swapping the sim into another phone and you would have everything accessible. Some phones had their own memory also so you could choose where to store it or it would revert to SIM when phone memory was out.
Problem was that the memory on the SIM was incredibly slow and small and had no support for advanced contact list management(like multiple numbers per name), so now every phone has its own storage.
Yes, my Nokia 8850 had no internal storage and therefore i could only hold 10 messages on the SIM. The later SIM's had more memory and could store 20 messages!
Seems strange having a phone that even stores them individually and doesn't group my contact these days!
Yeah, if it worked outside the US I'd be on it in a flash. I suspect Twilio will have local-to-me-in-Australia endpoints before Google Voice does, so a hand-rolled Twilio solution is probably in my future.
Didn't the original GSM phones work in a similar way, with no SIM and some sort of mapping to a phone number at the carrier end?
As far as I know (and recall), SIM was always part of the GSM specifications.
The first SIMs where credit card sized. Later generations where still credit card sized, but with a perforated breakout for the SIM as we know it (mostly).
The predecessor system (analogue mobile) didn't use SIM.
Ahhh, it was the old analogue phones I was thinking of. I never had one, my brother did though. I remember the big sim card and the perforated ones too :)
And while NMT phones didn't use easily (and user) replaceable SIM, they were paired to operator/number not by some database but by contents of replaceable EPROM chip in them. SIM cards were introduced not to make changing carriers possible, but easier and also more secure (NMT phones could be cloned without direct access to phone, only by eavesdropping on signaling channel).
Americans don't know that because their phone companies forbid that practice. AT&T doesn't even bother to move your SIM card from your old iPhone to your new iPhone when you upgrade, they just give you a new card.
When I switched from my old MotoRAZR to the iPhone, I used the same SIM. Just popped it in and I was good to go. My SIM still has the Cingular logo on it!
That's not correct. I've used my phone on multiple carriers just by swapping the SIM card - and when I upgraded my phone, they used my existing SIM card.
Really, they give you a new sim on upgrade? I can understand this if you are upgrading TO an iPhone since you need a micro SIM, but rather pointless otherwise.
I think I've had the same SIM card for about 6-7 years now!
My experience with AT&T is they've always given me a new SIM, when buying a new phone from them, but I've also bought raw sim's from them with no problem.
I think they just write the "New Phone" script for their employees, with a new sim, so the steps,are always the same. Less chances to mess things up when there are less choices.
I am now on T-Mobile (from AT&T) and there are all sorts of T-Mobile features that may or may not work depending on what SIM card you have in your phone. And if they don't work you have to get a new SIM card (that is not guaranteed not to disable other features.)
What!? That seems to be the weirdest thing ever. What is going on?
And complete anonymity. Most people don't care about this, but some of us do, sometimes. You buy a pay as you go sim card for £10, pay with cash, and toss it a week or month later.
Retailers are supposed to take your name and address when buying a PAYG phone/SIM with cash. I've seen a Carphone Warehouse refuse a sale because of it - although they also don't verify the information you give them, so you could just lie.
You have to replace the handset too; calls are likable both to sim and equipment. Buying a prepaid handset with CDMA account esn built in is just as anonymous.
This is currently hung on the SIM. Couldn't it just as well be hung on a web service, or paypal account? Why make it physical? This screams for virtualization.
The nice thing about having a physical object is that I can hand it easily to someone else, I can destroy it, I can save it, and I can do all these things when my service provider has disconnected me.
This is exactly what happened with the original analog and CDMA networks. Most carriers these days have converged on the HSPA and LTE standards which thankfully support SIM cards.
There's no technical reason why CDMA networks couldn't have supported SIM cards in their phones, but it was just never done. As evidenced by the overwhelming popularity of SIM cards, this particular battle has been won by almost unanimous decision in favour of the cards.
Only a few bastions of the original CDMA networks still don't natively support SIM cards (e.g. South Korea). But on the whole, it was already decided that SIM cards are here to stay since carriers demonstrated that without them, they are more prone to higher switching costs.
> There's no technical reason why CDMA networks couldn't have supported SIM cards in their phones, but it was just never done.
Indeed. RUIMs (and CSIMs) were standardized for CDMA, but carriers in the americas never bothered with them. A fair number of asian countries have CDMA carriers that use the, though.
That's been the case for ages because Verizon is a CDMA network, not GSM -- GSM takes SIM cards, while CDMA does not. Different tech.
This is likely to shift as V rolls out LTE, which DOES take SIM cards. So we're actually likely to see more intercompatibility as things progress. Except, of course, that everything's still likely to be carrier-locked.
Pardon my ignorance, but being in Europe means I've never used a 2G CDMA network - the iPhone4S supposedly works for both GSM and CDMA; if you don't get a SIM, does the CDMA module only work if you bought the phone from a CDMA network operator, and not if you bought it from Apple directly?
> does the CDMA module only work if you bought the phone from a CDMA network operator
Yes. They program it with your subscriber number at purchase. Technically they could reprogram phones not sold by them with your subscriber number, but they don't (to force you to give them more money).
There does exist a CDMA version of the SIM (RUIM? something like that). China Mobile uses it, and I think au/kddi do too. American carriers do not.
It gets worse in Canada. They carrier lock the phones to the brands. There's a big phone company called Telus that has a brand called Koodo and you can't swap phones between them even though it's actually the same network. All the joys of fake competition with none of the compatibility!
CDMA carriers can activate a phone not sold by them by ESN. However, some carriers have decided that they would prefer you to buy a handset from them and refuse to activate devices that weren't sold by them. Sprint has a policy of not activating any ESN that comes from a phone they didn't sell. I'm not sure if that applies to the iPhone since a non-Sprint iPhone would really be the same device. Anyway, unlike SIM cards, you're more at the mercy of whether a carrier will activate it or not.
ESN is equivalent to IMEI in GSM/UMTS networks. IMEI is tied to equipment, and never changes, just like ESN.
CDMA networks use IMSI to identify subscribers (as opposed to the equipment serial number) just like GSM/UMTS. IMSIs are provisioned on to the phone by the carrier with special software supplied by the phone manufacturer, instead of being supplied to the phone by the phone asking the SIM for it.
There's no technical reason why CDMA networks can't use a removable card to store subscriber data, and indeed there are a few standards for doing so (RUIM and CSIM) and a few carriers that use them.
My understanding from a friend in the telecom business is that, because the network operates at higher power, you need fewer towers for the same coverage area as GSM (GSM has a limit of something like 30km from a tower). And it tolerates multiple users in the same frequency space better than GSM and is less prone to interference from terrestrial radio signals.
A heck of a lot, and all current phone standards are based on it including current GSM.
GSM used TDMA which sliced a frequency into time slots. The time slots are allocated to the phones whether there is talking or not. This also leads to a fixed number of connections per frequency, and adjacent towers can't use the same frequency. It is also not forwards compatible since the phones expect certain behaviour from other phones in terms of using the time slots. That is why GSM carriers had to go out and get new frequencies when they added 2G data.
CDMA just has all phones broadcast at once. The phones merely see others as noise. When there isn't anything to transmit (voice calls have a lot of silence) then not much is transmitted. The tower will direct power levels to phones to keep the noise as low as possible. The net effect is that there isn't a fixed number of connections per tower/frequency, adjacent towers can use the same frequencies and it is forwards compatible - other phones can use newer versions and it won't affect current phones. CDMA is a lot harder engineering.
Here are a bunch of articles describing it in more detail from someone who worked on it.
Depending on how you look at it, there can be many benefits, but as with most technologies, they're contextual.
CDMA uses 1.25MHz channels. That can be limiting in some ways, but advantageous in others. When deploying UMTS channels, AT&T or T-Mobile would need to clear out 10MHz of spectrum. Back when 3G wireless was first getting off the ground, it was decently common for a carrier to have below 30MHz in a market. To give two examples, Sprint and T-Mobile both had an average spectrum depth of around 25MHz. Sprint was able to get out of the gate fast on 3G requiring only 2.5MHz (around 10% of their spectrum) to deploy. T-Mobile had to wait until it purchased new AWS spectrum years later. The UMTS channels would have taken up 40% of their spectrum. So, it was difficult to clear out enough space to deploy UMTS. You were basically taking a third to half of your spectrum and making it unavailable for current customers. Then, as you launched the network and started selling 3G devices, customers would start moving their usage to the new technology. EV-DO (the CDMA data standard), on the other hand, only required a carrier to free up 2.5MHz of spectrum to deploy 3G. Even today, it can be an issue. As the number of GSM customers dwindle, AT&T and T-Mobile want to allocate more spectrum to UMTS. However, they can only do that in 10MHz chunks. They don't get to say, "ah, there's 3MHz that we should move to UMTS".
Likewise, because UMTS does voice and data, it meant that carriers had to install SS7 and mobile switching gear to handle the voice. EV-DO was an all-IP network that wasn't going to handle voice. While that could be a disadvantage in some ways, it provided the benefit of being easier to deploy in terms of equipment.
Taking that a step further, the lack of a voice requirement for EV-DO meant that they could launch a network in a much more piecemeal fashion. If one launched a UMTS network with lots of holes, call quality would be poor. Sure, calls could hand-off to GSM, but they might have a "1-bar" UMTS signal with crummy call quality while GSM users got excellent quality. Back then, if data didn't work or was delayed a bit, it didn't matter that much. People used data infrequently compared to calling and call reliability is what people paid for.
It should also be noted that when EV-DO was first deployed, it was faster than UMTS. UMTS R99 had a peak data rate of 384kbps, well below the 2.4Mbps of EV-DO Rel 0. Now, the wider band of UMTS made it more future-proof, but initially EV-DO looked very good.
To be fair to UMTS, I could talk about problems with CDMA as well. CDMA offered a bit more of a practical, easier transition to 3G for carriers. It's narrower channels made it easy to carve out spectrum, the fact that there wasn't a voice component meant that less equipment was needed and it didn't require the same initial reliability, etc.
CDMA also has better voice quality, although I'm not sure if this is a bandwidth thing or a codec thing, and not sure how universal it is on deployed networks.
It doesn't interfere with your speakers when transmitting? I'm not sure if this is still the case, but my old AT&T phone would cause my speakers to go haywire when I was about to receive a phone call. Never experienced that with Verizon or Sprint.
What are you talking about? GSM dates back to the mid 1980s and the first spec was published in 1991. The first mobile phone CDMA standard didn't come into play until 1995.
I will definitely be shopping more carefully the next time I purchase a phone. I have an AT&T iphone 4. It works well, I have good coverage, and it can be used internationally, but AT&T will never unlock a phone, even after your contract is up, or if you are traveling overseas. I was in Europe for a week, and as soon as the phone connects, I get a text from AT&T saying that the data rate is $19.97/MB! Data was off, because I knew it would be a rip-off, but I had not guessed to what extent.
