Wesley's Tool-Box

I usually use somewhere between 5 to 7GB of cellular (mobile) data per month on my iPhone because my data plan gives me 6GB and I make sure not to go over too much. But since last December, I started to notice an unintended, excessive data consumption which caused my monthly usage to hover around 9 to 12GB until April. It then subsided for a while, but it came back last month. I didn't want to pay the carrier more than what I actually used, so I decided do something about it.

The root of this problem has been pinpointed to "Documents & Sync" activity under "System Services" category from fairly early on. You can see that it consumed 6.6GB of data by itself last month, out of 11.51GB total. The difficult part was determining what exact services were causing it, since there were many iOS features depending on synchronizing data and documents to iCloud. After much trial and errors, I was able to find two of them which caused most, of not all, of the issues.

One was the Photos app using the data connection to update Shared Albums and iCloud Photos. This was a bit strange because I have disabled iCloud Photos and my Shared Albums see barely any activity. Still, it had caused a burst of data consumption from time to time, spending up to nearly 1GB in about 10 minutes in the worst case and making the phone hot in the process. After disabling cellular data option within the Photos entry in the Settings app, these bursts were no more.

The other was the iCloud Drive. When I disabled its cellular data use by using the option buried at the bottom of the Cellular entry in the Settings app, the remaining excess usage stopped. Come to think of it, the data consumed during normal use, be it using the camera, browsing the internet, or interacting with the social media, was roughly twice the previously normal level. So whatever I did, the iCloud Drive was trying to sync some undetermined data in parallel, even though I had no intention of letting it do that. The available space in the Drive did not change, so I would guess it was some sort of system-level stuff.

By the way, the Internet searches I did while trying to fix this problem revealed that a lot of people had similar experiences, but with slightly different solutions. Some people had success by adjusting settings related to iMessages or Keychain, to name a few. So my solution may not be definitive for everyone and you should treat it as a starting point.

LTE is the 4th generation (4G) wireless data communication standard that supersedes WCDMA and other 3rd generation (3G) ones. Unfortunately, the far more diverse range of frequencies that the carriers around the world uses for this standard is a big headache, especially for Apple.

This is because a single model of iPhone tries to support as much of the entire world as possible in order to simplify the lineup. iPhone 4S, the last model before LTE support, indeed came in a single model for the entire world. In contrast, iPhone 5 and 5S had to be split up into multiple models that each had differing LTE band support. This was largely because the chipset couldn't support all the needed bands at once.

This meant that an iPhone bought in one country may not support LTE in another country. With iPhone 5, you needed model A1429 (for Sprint and Verizon in US) if you wanted it to use LTE in Korea. A1428 (for AT&T and T-Mobile in US) wouldn't do. That may have been a factor in the Korean carriers not automatically enabling LTE for foreign phones until 2014.


If you wanted to use LTE, you had to take your phone to a carrier branch or a certified store to have the device manually registered as being LTE capable. My AT&T iPhone 5S was put in as an "OMD Apple LTE Handset" on the SK Telecom network. Come 2014, though, this situation was largely resolved. Not only would your iPhone from overseas work with the LTE network, iPhone 6 and 6 Plus had worldwide LTE band support regardless of the specific model.

Situation is similar with iPhone 6S and 6S Plus, which adds a few more obscure or upcoming LTE bands on an already extensive array of support. There are still three specific models for each type, but one is for adding an upcoming AT&T-specific band 30 (A1633, A1634) and the other is for Chinese release (A1700, A1699). They are identical to the general model (A1688, A1687) otherwise.


However, not everything is in the clear. VoLTE (LTE-based voice calls) support is still not a universally supported feature among phones and carriers are still enabling this on a manual basis as of this writing. Owners of internationally bought iPhone 6, 6 Plus, 6S, and 6S Plus still need a visit to the carrier branch or store.

I had two iPhone 6S Plus that came from overseas - one is a "SIM-Free" version from Japan that you saw in my earlier post and the other is from United States intended for T-Mobile network. Both are model A1687 and the same version expected to be sold in Korea in a few days' time (October 23, 2015). The former was registered at an SK Telecom branch office as "OMD Apple VoLTE", the same title my iPhone 6 Plus received last year. The latter was registered at a local certified SK Telecom store as "OMD Apple VoLTE_6S" as shown here. Only after doing this, and waiting for a while to let the network know of the change, did the VoLTE function start to work.

The interesting (or cumbersome) part of doing the registration at a certified store was that it required me to have a separate, pre-registered device that was not in use to help with the registration. According to the store, once I inserted the SIM card into my iPhone 6S Plus, the network automatically registered it under "OMD Default Handset" because it wasn't recognized. In order to change that, the SIM card had to be put into another device so as to make the 6S Plus not be associated with any SIM card. Only then could the re-registration could proceed. Branch offices didn't have this requirement, so I have to assume that the system provided to the store is limited compared to the branch.

For nearly a month, I've been using my iPhone 6 Plus every day. As one of the first users of such device in Korea, I decided to take an in-depth look at its improvements and functions whenever I can, to show what the Korean users are going to get soon. Now all the hard work is done, and I present to you the summary of all the reviews I wrote about it.

iPhone 6 series will finally launch in Korea officially on October 31, 2014, according to Apple's official announcement, and carriers are preparing to accept pre-orders about a week before that. I hope these reviews will help you decide if iPhone 6 Plus is right for you.

Preview	Summary
	0. One of the first iPhone 6 Plus in Korea (2014-09-19)
	Wesley gets his iPhone 6 Plus on the first launch day in Japan and brings it to Korea.
	1. iPhone 6 Plus - Unboxing & First Look (2014-09-22)
	The box containing the iPhone 6 Plus is opened up, and the phone is taken an all-around look. The bump caused by the camera lens is also examined.
	2. Protecting my iPhone 6 Plus (2014-09-23)
	Front and back side protection films are applied to the iPhone 6 Plus. Then, it is put inside a belt case intended for Galaxy Note series. Apple's own leather case is also tried out.
	3. Sizing up the shape & size of iPhone 6 Plus (2014-09-23)
	The size, thickness, and shape of the iPhone 6 Plus gets compared to other devices. It is first compared to other iPhones and iPads, then to a comparatively-sized Android smartphone.
	4. iPhone 6 Plus - LTE Compatibility & Speed (2014-09-24)
	Unlocked iPhone 6 Plus bought overseas is found to have LTE working on Korea's SKT & KT networks automatically. Also, real life LTE speed comparison is made between the 6 Plus and the 5S.
	5. iPhone 6 Plus - VoLTE Compatibility (2014-09-25)
	Initially, all calls were made in 3G mode despite changing the settings to allow VoLTE. To have the VoLTE actually working, a visit to an SKT branch office and a device registration process was needed.
	6. Testing iPhone 6 Plus battery w/o bending (2014-09-29)
	Real-life battery discharging and charging tests are performed simultaneously on iPhone 6 Plus and iPhone 5S to see the difference. Belt cases made sure the phones didn't bend.
	7. iPhone 6 Plus - General Performance (2014-10-01)
	Performance comparison across multiple apps are made between iPhone 6 Plus and iPhone 5S. This included 3DMark, Geekbench, and various JavaScript tests.
	8. iPhone 6 Plus - Camera's Quality (2014-10-01)
	Compared to iPhone 5S, the camera on the iPhone 6 Plus has improved dynamic range and enhanced night time photography performance. Image stabilization works well, too.
	9. iPhone 6 Plus - Camera's Speed (2014-10-04)
	The focusing performance of the iPhone 6 Plus is noticeably more advanced than iPhone 5S. Burst mode shooting and slow-motion video recording also saw improvements.
	10. iPhone 6 Plus - M8 Motion Co-processor (2014-10-08)
	The M8 motion co-processor and its new barometer are tested out by walking up the stairs and seeing how many floors are registered. Other uses are also taken a look at.
	11. How far does iPhone 6+ & SKT's VoLTE go? (2014-10-13)
	How the SK Telecom's network treats the attempts to make a VoLTE call from iPhone 6 Plus varies by how the person at the other end is connecting. All the possibilities are tested.
	12. Thoughts on a month of iPhone 6 Plus use (2014-10-14)
	Using the iPhone 6 Plus one-handed is not as convenient as Apple would hope. However, the big screen that caused this also offers many benefits that maybe considered as worthy trade-offs.

As I mentioned in the previous VoLTE post, all three major mobile carriers in Korea have been supporting VoLTE for quite some time now. One glaring problem, though, is that cross-carrier VoLTE still hasn't been realized, despite years of negotiations. This seem to have introduced some confusion. The truth is that a device can always request a VoLTE call, but it's up to the network to decide to go with it, and if so, fully or just on the surface.

In the case of LGU+, the carrier's aging "2G" CDMA network had been a weak point, so it worked hard to have everything done on LTE, even voice. That's why it'll accept a phone that can do VoLTE even if it doesn't support the needed CDMA frequency band - namely, the iPhone 6 series. ( One caveat is that they are not accepted for registration on the network yet until official Korean debut. This is largely a decision of policy, not technicality. ) If you have such a phone, all calls will be connected as VoLTE no matter what.

But in case of SK Telecom (SKT) or KT, their "3G" WCDMA networks are still widely used. So they don't have the urge to go fully LTE. A call could still be made on either 3G or LTE, depending on the situation. No handsets on these networks get to make all of its calls on VoLTE.

Since I'm on SKT, I made calls to various phone numbers on my VoLTE phone, iPhone 6 Plus, to see how they end up connecting, and what quality they were.

Case	Caller 1	Caller 2	Connect 1	Connect 2	Quality
1	SKT VoLTE	SKT VoLTE	LTE	LTE	HD Voice
2	SKT VoLTE	SKT 3G (AMR-WB)	LTE	3G	HD Voice
3	SKT VoLTE	SKT 2G/3G	LTE	2G/3G	Normal
4	SKT VoLTE	KT / LGU+ VoLTE	LTE	LTE	Normal
5	SKT VoLTE	KT / LGU+ 2G/3G	LTE	2G/3G	Normal
6	SKT VoLTE	Landline (02 ~ 064)	LTE	Landline	Normal
7	SKT VoLTE	Toll Free (080)	LTE	Landline	Normal
8	SKT VoLTE	Special (15xx, 3-digit)	3G	Landline	Normal
9	SKT VoLTE	VoIP (070)	3G	Internet	Normal

As of this writing, two types of phones on the SKT network, the VoLTE-enabled phones (case 1) and the AMR-WB supported phones without VoLTE (case 2), can make end-to-end HD Voice-quality calls to and from iPhone 6 Plus. AMR-WB codec is the same codec used by VoLTE, but some phones support this only on 3G at a lower bitrate, e.g. iPhone 5 and Xperia Ray.

As mentioned earlier, cross-carrier VoLTE agreements are not yet in place, so calling VoLTE phones on other networks (case 4) ends up degrading quality. I'm hoping this clears up soon because there's no technical reason to be like this.

Meanwhile, most calls connect via LTE, with the exception of special numbers such as the three-digit numbers (including emergency) and the 15xx, 16xx numbers that companies use (case 8), as well as the VoIP numbers with the 070 area code (case 9). I understand that these numbers don't connect with high-quality codecs so LTE connection isn't necessary, but it doesn't explain why regular landline connections do connect via LTE.

Cellular communications have traditionally used separate voice and data channels. But with the advent of smartphones, bulk of the communications now happen on the data channel. It's no coincidence that only the data channel remained by the 4th generation (4G) technology. To carry voice, though, a fallback to 3G or older technology's voice channel was initially needed. But VoLTE (Voice over LTE) came onto the scene to do away with this by letting the data channel handle voice as well.

As with many technologies, Korea was a forerunner in adopting VoLTE. World's first commercial VoLTE service was launched more than two years ago by two of the three major Korean carriers, SK Telecom and LG U+. The remaining one, KT, joined mere two months later. Worldwide adoption didn't really take off until earlier this year, however. About a dozen carriers around the globe now have it. Noting this trend, Apple has decided to enable the capability in the iPhone 6 series.

So naturally, I wanted to see VoLTE on my iPhone 6 Plus in action. It can be enabled in the Settings app by going to Cellular and selecting "Voice and Data" option for LTE. The previous 5/5C/5S models simply have toggle switch for LTE instead, even with iOS 8.0 update. After that, I made voice calls to a lot of different lines, including a VoLTE-enabled phone on the same carrier. But every time, the connection indicator turned from LTE to 3G, showing that VoLTE wasn't working.


I checked to see how the network recognized my iPhone 6 Plus. It was being listed as an OMD Default Handset, the same name that my iPhone 5S was given when it was brought in from the US. In other words, a generic device that it doesn't recognize. Perhaps the network couldn't tell whether the device had a VoLTE capability, so it simply ignored its attempts. It was time to visit my carrier's branch office to get to the bottom of this.

LTE frequencies tend to be quite varied because it has to be either laid alongside or replace the existing 2G and 3G networks. Even so, Apple tries to support as much frequencies as possible because it will reduce the number of region-specific models. Unfortunately, iPhone 5S and 5C each sprawled to five different models, so people asked around whether their iPhones would work on another country's LTE network. I even wrote about iPhone 5S's LTE network compatibility last year, and it has the longest comment thread in this website.

This time around, though, the number of models were reduced to a much more manageable two for both iPhone 6 and 6 Plus. The massive 20-band support did the trick. The good news here is that, if you bought an unlocked iPhone 6 or 6 Plus anywhere in the world and come to Korea, the LTE will work with all three local carriers. Korea should get A1586 / A1524 models on sale in a couple of months, but A1549 / A1522 models often found in United States or Canada should work, too.

After I brought the A1524 iPhone 6 Plus from Japan to Korea, I put the SIM card from my 5S and turned it on. The device had no problems connecting to SK Telecom's LTE network right away. I've confirmed that the situation is the same when you're on KT's network, as well. It seems that the network no longer goes into 3G mode when it sees an unrecognized LTE device, which used to be the case when I brought the iPhone 5S from United States last year.


Meanwhile, the top speed for LTE data on iPhone 6 series was pushed to 150Mbps from 100Mbps of 5/5C/5S. The bleeding edge phones in Korea are always a step ahead - 150Mbps was possible when iPhone 5 came out and the recent models can do 225Mbps - but with low monthly data caps, they are little more than technology show-off right now.

In any case, I wanted to see how fast the iPhone 6 Plus can do LTE data in real life, so I ran a speed test app. As you can see here, it can go almost up to 100Mbps. Pretty good, but that's how fast an iPhone 5S could supposedly do, as well. Obviously, a side-by-side test was needed.

Some interesting claims have been raised about various things related to iPhones on a local forum, so I'd like to lay out what I know of this subject.

On the eve of the official sale of iPhone 6, there was a claim that the differentiating factor of the two different models (iPhone 6+: A1522 & A1524, iPhone 6: A1549 & A1586) lied in whether it was unlocked in the first place or not. The A1586 and A1524 models were supposedly the unlocked ones, as it basically covers all LTE bands around the world, and thus being a "world phone" of sorts.

The truth is, iPhones being locked to a carrier or not never really depended on a specific model number. Let's see the A1584 / A1524 first. They're going to be sold by the three telecom companies in Japan.

[iPhone LTE Information]

The Japanese carriers are known to apply carrier locks to the models sold on contracts, while the Japanese Apple Stores also carry the unlocked ("SIM-Free") versions as well. So, those models would have both carrier locked and unlocked versions.

Now let's take a look at the A1549 / A1522.

Verizon and T-Mobile in the United States have the phones unlocked, in terms of GSM/WCDMA. For AT&T, if you're buying at a discounted price on contract, carrier lock will apply. In Canada, the Apple Stores have the unlocked versions.

So the iPhones may be locked or not regardless of the model number. Model numbers are tied to what carriers they will be sold from.

As for Korea, I predict that the A1586 / A1524 will be the ones to be released, if iPhone 5S is any indication. For the 5 and 5S models, the ones released in Hong Kong subsequently saw light in Korea. A1586 / A1524 are to be released in Hong Kong in the cases of iPhone 6/6+.

The models released in Korea have been unlocked since iPhone 4S regardless of whether it was sold by a carrier or not, so iPhone 6/6+ will be no different.

As for the Korean wireless certification issues in terms of import regulations, some considerations are needed. The certification is done by the model number, so once the process completes (Apple Korea applied for the certification on September 11), the iPhone 6/6+ models sold in places like Japan or Hong Kong should technically be certified as well.

But since the KCC certification logo may be missing on the back, you may have to provide the proof of the certification and the model number on the phone should import process stall. There's an exemption for personal import of one uncertified device per person, but this is indeed for the uncertified ones, so it couldn't be used against importing a certified one. But if this doesn't solve the issue, it's not clear how to go about it since there aren't many reports relating to this.

For service & repair, iOS devices come with local warranties by default. This is pointed out on the warranty itself.

[Apple iOS Hardware Warranty]

"Apple may restrict warranty service for iPhone and iPad to the country where Apple or its Authorized Distributors originally sold the device."

This appears on the other countries' versions as well. In fact, even the Hong Kong versions of iPhones, which bear the same model numbers as the Korean counterparts, have often been reported to have the repairs turned down in Korea.

There is a mention on the information on the unlocked version that, if you want to use it overseas you should get that version. But this is because you can use the local SIM card while traveling. Carrier-locked version prevents that. The Japanese version of the information was less than clear on that, but the Canadian version was better worded.

About the Unlocked iPhone (Japan)

"複数年のサービス契約を結びたくない場合や、海外で地元の通信事業者を使いたい場合は、SIMフリーのiPhoneを選ぶことをおすすめします。"
"If you don't want a multiyear service contract, or if you want to use a local carrier overseas, the SIM-Free iPhone is recommended."

About the Unlocked iPhone (Canada)

"If you don’t want a multiyear service contract, or if you prefer to use a local carrier when traveling abroad, the unlocked iPhone is the best choice."

In other words, Apple never said "if you bought the phone from overseas and bring it home, you can ask for a repair locally" on that page. If you could get one repaired, then you were lucky, not because the policy allowed it to happen.