Monday, September 30, 2013

NTT docomo does not prevent unbranded devices from connecting to LTE network

There are now several posts online that describe using the Nexus 7 LTE with various Japanese SIM cards. Unlike the iPhone (and just as I expected) there appear to be no problems getting a connection with an unlocked, unbranded device on docomo's "Xi" LTE network. LTE service, both direct from docomo and through an MNVO, works perfectly.

N7 APN settings (Image source).

Until now, we couldn't rule out a "server-side" origin for the problems that unlocked iPhone 5 users encounter when trying to connect to docomo LTE. This was because, except for those provided by docomo, there were no other LTE devices that supported docomo's primary LTE frequency (Band 1, 2100 MHz). We had two variables (iOS software and docomo servers), and one equation (Apple hardware), which is unsolvable.

We can now safely say that 3rd party devices are not subject to an across-the-board lock out from "Xi" LTE.

Prospects for unlocked iPhone 5S and 5C in Japan

It still remains unclear (due to lack of testing) what will happen when an unlocked iPhone 5S or 5C is brought to Japan. iOS is well known for disabling the ability to easily alter APN settings depending on the SIM card that is inserted. As mentioned in comments on another post, the iPhone Configuration Utility can be used to create configuration files that add new APNs, and this is used by some MVNOs to work around disabled APN settings. However, as I noted earlier, the docomo carrier bundle appears to prevent attaching to 3G and LTE networks with anything other than the sp-mode APN. If this is the case, it could render the configuration utility useless if these same rules are included on unlocked iPhones as well.

The sp-mode APN is filtered by IMEI number on the "server side." Only whitelisted devices (sold by docomo) can connect.

Nexus 7 LTE SIM options

The Shukan Ascii article compares different LTE SIMs in the Nexus 7. I'll briefly translate and summarize the contents in another post when I have more time.

In short, Docomo Xi SIMs work and are recommended by Shukan Ascii. You will need either:
  1. a subscription to docomo's Mopera ISP ( APN) or
  2. a contract with a docomo MNVO.
You cannot take a docomo SIM from a normal docomo LTE phone and put it in the Nexus 7. Most all docomo phones now use the sp-mode ISP. The Mopera ISP must be used.

A contract change was also required to get a KDDI SIM to work, but as I suspected, coverage is not the best (though better than expected in the Tokyo metro area). Emobile SIMs are not yet compatible pending a firmware update.

Shukan Ascii weren't able to get the Softbank LTE SIM to work with anything except regular 3G, but they admit they didn't try very hard. I know of at least one person claiming to have softbank LTE and an iPhone SIM card working with Android.


  1. So very oddly it seems that the docomo carrier bundle will not install on the iphone 5. The APN settings are all in the carrier bundle. On an unlocked phone you can change them based on your carrier bundle that matches. I have put the iphone sim in my unlocked iphone 5 expecting for it to work like the Softbank LTE sim does, but no dice. It performs exactly as my standard XI sim does.

  2. No idea what's up with iPhone 5, but I get 4G on my Lumia 920 without a problem, on Docomo's Xi.

    I used to run an iPhone 4 (black) SIM inside an unlocked Android phone, without a problem.

  3. (cross question from a related thread) Does this mean that voice will work when using the APN with and Xi SIM, or just data?

  4. Just read about OCN mobile One at
    Has anyone used this ???

  5. Can confirm an unlocked Australian iPhone 5S can connect to Docomo LTE network.
    Unlocked Australian iPhone 5 will still not connect to Docomo LTE network even when using same sim as for 5S above.

  6. Update - at first the unlocked 5S connected on the Docomo including LTE but then after a few hours, the LTE dropped off and so did the connection as a whole - APN setting option had dissappeared. Then had to use the apn file on a previous article which has provided connection again back to but not at LTE service side - standard 3G only.