Wednesday, October 5, 2011

AU iPhone will not work with other CDMA carriers

[Clarification: Roaming will of course be possible on e.g., US Verizon's network. Contracting service on Verizon with an AU iPhone is extremely unlikely. And added a better explanation of RUIM cards in AU handsets.]

I thought I'd preemptively head off any questions ;-)

AU handsets do have a SIM-like "IC card" (RUIM), and it does in fact look exactly like a SIM card. However it does not serve the exact same purpose in the case of an AU handset. When KDDI presented arguments against SIM unlocking, they pointed out that simply switching the RUIM card between two handsets would not allow two AU customers to swap phones. This is because AU CDMA-2000 handsets are internally registered to both the network and the subscriber.

Unless something drastically changes, an AU iPhone will not be usable with US Verizon or Sprint, nor will the reverse be possible. (Roaming will be possible.) Also a softbank iPhone will not be usable on AU. Technically it is of course possible, but good luck getting AU to register it to their network.

In addition, the radio of the US version supports CDMA EV-DO Rev. A 800, 1900 MHz, while the Japanese version has 800 and 2100 MHz, the frequencies AU uses.

Quoting Apple's tech specs page in English.
CDMA available only if iPhone 4S is sold and activated for use on a CDMA network.
And Japanese
CDMAは、iPhone 4SをCDMAネットワークで使用する目的で購入およびアクティベートした場合にのみご利用いただけます。
So, now that we got that out of the way, the more important question is: Will there be a region-specific SIM lock on an AU iPhone to prevent you from taking it to a domestic WCDMA carrier or MVNO like softbank or bmobile? Remember the debacle surrounding the original Japanese iPad? (Honestly, I never figured out WTF was going on with the original iPad baseband and I didn't care enough to exert the effort to dig through all the smoke and mirrors, of which there was a lot.)


  1. Then you probably have to wait for the release of iOS5 as redsn0w seems to work with iOS5. Only a few days to go...

  2. Techniker TechnologeOctober 7, 2011 at 3:51 PM

    unless you a) a housewife amount of voice calls every month or b) family in japan that makes family contracts more attractive, the bulk of your monthly charges will be due to data. Expect a monthly bill of 10,000Yen+ if you are on Docomo, and maybe around 10,000 Yen for Softbank. Moreover you will be locked into a two year contract, with a carrier-branded phone.

    Therefore I strongly recommend going for b-mobile. Especially the 1GB UIM contract is very competitive, if you are essentially using your phone for mail, web, twitter and the occasional youtube video.

    For the phone, buying either your favourite Android-phone, or iPhone 3G/4G overseas (e.g. a Nexus One/Nexus S), (make sure it'll work with B-mobile) or going for the cheap option, the IDEOS.

    I am trapped in a Docomo contract and it's just too expensive to get out without loosing my phone number.

    In any event, I would recommend thinking twice before signing a two year contract on one of the major carriers.
    PS: I would also recommend to not ask any "average" Japanese person for advice, because the "average" Japanese person is stuck in a "walled-garden is the paradise" mentality and have usually no clue what is possible...

  3. Good advice. If you get the ss voice plan and tend not to go over, Docomo is doable for about &yen8,000/month. Which is still way more expensive than a Talking 1GB Flat rate. but less than 10,000 ;-)

  4. Thank you. You are right. I could wait for iOS 5 and use B-mobile. But I do need voice, not only data. Also I don`t like to be limited to what Apps I can use. The Talking 1GB plan sounds like it could be the one for me as it doesn`t seem to have any limits on App use and 1GB is plenty for me.

    Then again, an iPhone 4S 16GB at au is not much more expensive (all in 5760 / month, no setup charge) than b-mobile, but of course I would have to sign my soul off for two long years...not really an Android fan either, so I will now have to weigh those two options against another: Talking flat 1GB with a iPhone 4 or au data flat / voice with a "free" iPhone 4s

  5. Techniker TechnologeOctober 7, 2011 at 4:58 PM

    not sure.... well, if you are very disciplined. Just one lengthy (30min) conversation with the gf (if you are not married and not on a family plan), or a few WorldSMS or WorldCalls (sure, you know it is expensive... but sometimes you just have to call this or that person *now*) and the 1man barrier is breached again :-)

  6. > When KDDI presented arguments against SIM unlocking, they pointed out that simply switching the RUIM card
    > between two handsets would not allow two AU customers to swap phones. This is because AU CDMA-2000
    > handsets are internally registered to both the network and the subscriber.

    Sorry, I'm a little confused about this.
    I lent my friend one of my AU phones and she went down to au shop, got a sim card, and is now using that phone.
    I no longer have AU service since I switched to Docomo and had drawers full of previous AU camera phones.

    Does this mean that I'm still tied to the phone that I lent to my friend? Would AU then suddenly make me culpable for something should the unlikely event of something bad happen with my old phone that I lent away?

    Thanks and more thanks if someone can shed some light on that.

  7. At the AU shop, the staff didn't only change the RUIM card, they also changed the internal information. So no, you aren't still associated with that phone. If you also have an AU phone, try swapping cards with your friend and see if it works. Then get two Docomo or SBM users to try it. You'll see it works for the later but not with AU.

  8. Many thanks =)

    My personal disclaimer: It seems I'm too lazy to distinguish between UIM and SIM card... (even though I do get... it's just the changing vocabulary) so please excuse my proliferate use of the wrong ones =P

  9. Alex one link

  10. You are right. I mixed up redsn0w and ultrasn0w. Looks like it's not that easy anymore to jailbreak and unlock an iPhone.

  11. As far as I know, In Mainland China, the only CDMA carrier China Telecom also utilizes the RUIM card,
    but it can simply switching the RUIM card between two handsets to swap phones.
    I can't understand why au don't allow. It just simply making more trouble to its customers.
    By the way, somje Modified Verizon 4S that can use RUIM (Verizon don't use RUIMs) are on sale at Chinese-like eBay:
    However it can't use GSM SIMs by now, only CDMA RUIMs.
    but the price is very high, about 7800 yuan/each. (1225 USD/95500 JPY)

  12. Hi there I have a Au mobile phone and now the handset Im currently using has finally died out on me, I am on a contract and have paid for the mobile it's self so we just pay for the service ... I'm just wondering if I was to get a second hand AU handset from another store will I be able to use the Sim in another Au handset?

  13. Hi I'm wondering if you can help me at all. I've read this entire feed. Do you know how I can unlock an iphone 5 purchased in Japan and locked to AU KDDI? Im trying to use it in North America, but I am having alot of trouble researching this online. Am I reading right that AU does not allow phones held by them to even be unlocked? Any help would be greatly appreciated!!!