Apple Watch Unlock, 802.11ac, and Time


One of the benefits of upgrading to MacOS 10.12 Sierra is the ability to unlock my Mac laptop with my Apple Watch. Yet I’m not able to do that. Why? Turns out, the answer involves some pretty cool tech.

Somebody’s Watching You

The tech specs list the 2013 MacBook and higher as the minimum model needed to enable Watch Unlock on your Mac. You also need a few other things, like Bluetooth enabled and a Watch running WatchOS 3. I checked my personal MacBook against the original specs and found everything in order. I installed Sierra and updated all my other devices and even enabled iCloud Two-Factor Authentication to be sure. Yet, when I checked the Security and Privacy section, I didn’t see the checkbox for the Watch Unlock to be enabled. What gives?

It turns out that Apple quietly modified the minimum specs during the Sierra beta period. Instead of early 2013 MacBooks being support, the shift moved support to mid-2013 MacBooks instead. I checked the spec sheets and mine is almost identical. The RAM, drive, and other features are the same. Why does Watch Unlock work on those Macs and not mine? The answer, it appears, is wireless.

Now AC The Light

The mid-2013 MacBook introduced Apple’s first 802.11ac wireless chipset. That was the major reason to upgrade over the earlier models. The Airport Extreme also supported 11ac starting in mid-2013 to increase speeds to more than 500Mbps transfer rates, or Wave 1 speeds.

While the majority of the communication that the Apple Watch uses with your phone and your MacBook is via Bluetooth, it’s not the only way it communicates. The Apple Watch has a built-in wireless radio as well. It’s a 2.4GHz b/g/n radio. Normally, the 11ac card on the MacBook can’t talk to the Watch directly because of the frequency mismatch. But the 11ac card in the 2013 MacBook enables a different protocol that is the basis for the unlocking feature.

802.11v has been used for a while as a fast roaming feature for mobile devices. Support for it has been spotty before wider adoption of 802.11ac Wave 1 access points. 802.11v allows client devices to exchange information about network topology. 11v also allows for clients to measure network latency information by timing the arrival of packets. That means that a client can ping an access point or another client and get a precise timestamp of the arrival of that packet. This can be used for a variety of things, most commonly location services.

Time Is On Your Side

The 802.11v timestamp has been proposed to be used as a “time of flight” calculation all the back since 2008. Apple has decided to use Time of Flight as a security mechanism for the Watch Unlock feature. Rather than just assume that the Watch is in range because it’s communicating over Bluetooth, Apple wanted to increase the security of the Watch/Mac connection. When the Mac detects that the Watch is within 3 meters of the Mac it is connected to via Handoff it is in the right range to trigger an unlock. This is where the 11ac card works magic.

When the Watch sends a Bluetooth signal to trigger the unlock, the Mac sends an additional 802.11v request to the watch via wireless. This request is then timed for arrival. Since the Mac knows the watch has to be within 3 meters, the timestamp on the packet has a very tight tolerance for delay. If the delay is within the acceptable parameters, the Watch unlock request is approved and your Mac is unlocked. If there is more than the acceptable deviation, such as when used via a Bluetooth repeater or some other kind of nefarious mechanism, the unlock request will fail because the system realizes the Watch is outside the “safe” zone for unlocking the Mac.

Why does the Mac require an 802.11ac card for 802.11v support? The simple answer is because the Broadcom BCM43xx card in the early 2013 MacBooks and before doesn’t support the 802.11v time stamp field (page 5). Without support for the timestamp field, the 802.11v Time of Flight packet won’t work. The newer Broadcom 802.11ac compliant BCM43xx card in the mid-2013 MacBooks does support the time stamp field, thus allowing the security measure to work.

Tom’s Take

All cool tech needs a minimum supported level. No one could have guess 3-4 years ago that Apple would need support for 802.11v time stamp fields in their laptop Airport cards. So when they finally implemented it in mid-2013 with the 802.11ac refresh, they created a boundary for support for a feature on a device that was in the early development stages. Am I disappointed that my Mac doesn’t support watch unlock? Yes. But I also understand why now that I’ve done the research. Unforeseen consequences of adoption decisions really can reach far into the future. But the technology that Apple is building into their security platform is cool no matter whether it’s support on my devices or not.

FaceTime Audio: The Beginning or The End?


The world of mobile devices is a curious one. Handset manufacturers are always raising the bar for features in both hardware and software in order to convince customers to use their device. Yet, no matter how much innovation goes into the handset the vendors are still very reliant upon the whims of the carriers. Apple knows this perhaps better than anyone

In Your FaceTime

FaceTime was the first protocol to feel the wrath of the carriers. Apple developed it as a way to facilitate video communication between parties. The idea was that face-to-face video communications could be simplified to create a seamless experience. And it did, for the most part. Except that AT&T decided that using FaceTime over 3G would put too much strain on their network. At first, they forced Apple to limit FaceTime to only work with wireless connections. That severely inhibited the utility of the protocol. If the only place that a you can video call someone is at home or in a coffee shop (or on crappy hotel wireless) that makes the video call much less useful.

Apple finally allowed FaceTime to operate over cellular networks in iOS 6, yet AT&T (and other carriers) restricted the use of the protocol to those customers on the most current data plans. This eliminated those on older, unlimited data plans from utilizing the service. The carriers eventually gave in to customer pressure and started rolling out the capability to all subscribers. By then, it was too late. Apple had decided to take a different track – replace the need for a carrier.

Message For You

The first shot in this replacement battle came with iMessage. Apple created a messaging protocol like the iChat system for Mac, only it ran on iPhones and iPads (and later Macs). It was enabled by default, which was genius. The first time you sent an Short Message Service (SMS) text to a friend, the system detected you were messaging another iPhone user on a compatible version of software. The system then flipped the messaging over to use iMessage instead of SMS and the chat bubbles turned blue instead of green. Now, you could send pictures of any size as well as texts on any length with no restrictions. 160-character limits were no longer a concern. Neither was paying your carrier for an SMS plan. So long as the people you spoke with were all iDevice users the service was completely free.

iMessage was Apple’s first attempt to sideline the carriers. It removed a huge portion of their profitability. According to an article published at the launch of iMessage, carriers were making $.20 per message outside of an SMS plan for data that would cost about $.0125 on a data plan. Worse yet, that message traversed a control channel that was always present for the user. There was no additional cost to the carrier beyond flipping a switch to enable message delivery to the phone. It was a pure-profit enterprise. Apple seized on the opportunity to erode that profitability.

Today, you can barely find a cellular plan that *doesn’t* include unlimited text messaging. The carriers can no longer reap the rewards of a high profit, low cost service like SMS because of Apple and iMessage. Carriers are instead including it as a quality of life feature that they make nothing from. Cupertino has eliminated one of the sources of carrier entanglement. And they’re poised to do it again in iOS 7.

You Can Hear Me Now

FaceTime Audio was one of the features of iOS 7 that got swept under the rug in favor of talking about flat design or parallax wallpaper. FaceTime Audio uses the same audio codec from FaceTime, AAC-ELD, to initiate a phone call between two iDevice users. Only it doesn’t use the 3G/LTE radio to make the call. It’s all done via the data connection.

I tested FaceTime Audio for the first time after my wife upgraded her phone to iOS 7. The results were beyond astonishing. The audio quality of the call was as crisp and clear as any I’d every heard. In fact, I would compare it to the use of Cisco’s Wideband G.722 codec on an enterprise voice system. My wife, a non-technical person even noticed the difference by remarking, “It’s like you’re right next to me in the same room!” I specifically tried it over 3G/LTE to make sure it wasn’t blocked like FaceTime video. Amazingly, it wasn’t.

The Mean Opinion Score (MOS) rating that telephony network use to rate call clarity runs from 1 to 5. A 1 means you can’t hear them at all. A 5 means there is no difference between talking on the phone and talking in the same room. Most of the “best” calls get a MOS rating in the 4.1-4.3 range. I would rate FaceTime audio at a 4.5 or higher. Not only could I hear my wife clearly on the calls we made, but I also heard background noise clearly when she turned her head to speak to someone. The clarity was so amazing that I even tweeted about it.

FaceTime Audio calling could be poised to do the same thing to voice minutes that iMessage did to SMS. I’ve already changed the favorite for my wife’s number to dial her via FaceTime Audio instead of her mobile phone number. The clarity makes that much of a difference. It also helps that I’m not using any of my plan minutes to call her. Yes, I realize that many carriers make mobile-to-mobile calls free already. However, I was also able to call my wife via FaceTime Audio from my iPad as a test that worked perfectly. Now, I not only don’t use voice minutes but have the flexibility to call from a device that previously had no capability to do so.

Who Needs A Phone?

Think about the iPod Touch. It is a device that is very similar to the iPhone. In fact, with the exception of the cellular radio one might say they’re identical. With iMessage, I can get texts on an iPod touch using my Apple ID. So long as I’m around a wireless connection (or have a 3G MiFi device) I’m connected to the world. With FaceTime audio, the same Apple ID now allows me to take phone calls. The only thing the carriers now have to provide is a data connection. You still can’t text or call non-Apple devices with iMessage and FaceTime. However, you can reduce the amount of money you are paying for their services due to a reduction in the amount of minutes and/or texts you are sending. That should have the mobile carriers running scared.

Tom’s Take

I once said I would never own a cellular phone because sometimes I didn’t want to be found. Today, I get nervous if mine isn’t with me at all times. I also didn’t get SMS messaging at first. Now I spend more time doing that than anything else. Mobile technology has changed our lives. We’ve spent far too much time chained to the carriers, however. They have dictated what when can do with our phones. They have enforced how much data we use and how much we can talk. With protocols like FaceTime Audio, the handset manufacturers are going to start deciding how best to use their own devices. No carrier will be able to institute limits on minutes or texts. I think that if FaceTime Audio takes off in the same way as iMessage, you’ll see mobile carriers offering unlimited talk plans alongside the unlimited text plans within the next two years. If 50% of your userbase is making calls on their data plans, they need for all those “rollover” minutes becomes spurious. People will start reducing their plans down to the minimum necessary to get good data coverage. And if a carrier decides to start gouging for data service? Just take your device to another carrier. Or drop you contact in favor of a MiFi or similar data-only connection. FaceTime Audio is the beginning of easy Voice over IP (VoIP) calling. It’s the end of the road for carrier dominance.

iOS 7 and Labels


Apple is prepping the release of iOS 7 to their users sometime in the next couple of months. The developers are already testing it out to find bugs and polish their apps in anticipation of the user base adopting Jonathan Ive‘s vision for a mobile operating system. In many ways, it’s still the same core software we’ve been using for many years now with a few radical changes to the look and feel. The icons and lack of skeumorphism are getting the most press. But I found something that I think has the ability to be even bigger than that.

The user interface (UI) elements in the previous iOS builds all look very similar. This is no doubt due to the influence of Scott Forestall, the now departed manager of iOS. The dearth of glossy buttons and switches looked gorgeous back in 2007 when the iPhone was first released. But all UI evolves over time. Some evolve faster than others. Apple hit a roadblock because of those very same buttons. They were all baked into the core UI. Changing them was like trying to correct a misspelled word in a stone carving.  It takes months of planning to make even the smallest of changes.  And those changes have to be looked at on a massive scale to avoid causing issues in the rest of the OS.

iOS 7 is different to me.  Look at this pic of an incoming call and compare it with the same screen in iOS 6:

iOS 7

iOS 7

iOS 6

iOS 6

The iOS 6 picture has buttons.  The iOS 7 picture is different.  Instead of have chiseled buttons, it looks like the Answer and Decline buttons have been stuck to the screen with labels.  That’s not the only place in the UI that has a label-like appearance.  Sending a new  iMessage or text to someone in the Messages app looks like applying a stamp to a piece of paper.  Taking all that into consideration, I think I finally understand what Ive is trying to do with this UI shift in iOS 7

Labels are easy to reapply.  You just peel them off and stick them back on.  Unlike the chiseled-in-stone button UI, a label can quickly and easily be reconfigured or replaced if it starts to look dated.  Apple made mention of this in Ive’s iOS 7 video where he talked about creating “hierarchical layers (to) establish order“.  Ive commented that this approach gives depth to the OS.  I think he’s holding back on us.

Jonathan Ive created UI layers in the OS so he can change them out more quickly.  Think about it.  If you only have to change a label in an app or change the way they are presented on screen, it allows you to make more rapid changes to the way the OS looks.  If the layers are consistent and draw from the same pool of resources, it allows you to skin the OS however you want with minimal effort.  Ive wasn’t just trying to scrub away the accumulation of Scott Forrestal’s ideas about the UI.  He wanted to change them and make the UI so flexible that the look can be updated in the blink of an eye.  That gives him the ability to change elements at will without the need to overhaul the system.  That kind of rapid configurability gives Apple the chance to keep things looking fresh and accommodate changing tastes.

Tom’s Take

I can almost hear people now saying that making future iOS releases able to be skinned is just another rip off of Android’s feature set.  In some ways, you are very right.  However, consider that Android was always designed with modularity in mind from the beginning.  Google wanted to give manufacturers and carriers the ability to install their own UI.  Think about how newsworthy the announcement of a TouchWiz-free Galaxy S4 was.  Apple has always considered the UI inviolate in all their products.  You don’t have much freedom to change things in iOS or in OS X.  Jonathan Ive is trying to set things up so that changes can be made more frequently in iOS.  Modders will likely find ways to insert their own UI elements and take these ideas in an ever more radical direction.  And all because Apple wanted to be able to peel off their UI pieces as easily as a label.