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You are here: MacNN Forums > News > Tech News > In with the new: USB-C connector on new MacBook explained

In with the new: USB-C connector on new MacBook explained
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NewsPoster
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Mar 17, 2015, 04:38 PM
 
Apple spent very little time detailing USB Type C alongside its new MacBook -- this is expected, given the magnitude of the overall announcement. Despite a spec for it being released in parts over the last two years, USB Type C isn't well understood, and we'd like to help. So, once again, MacNN and Electronista have pored over some of the technical documents so you don't have to.

The full USB Type C spec revealed in late 2014 is actually USB 3.1, not USB 3.0. Apple's implementation on the new MacBook is USB Type C Generation 1, which isn't quite USB 3.1, but utilizes the same connector -- more on that in a bit. To help transition users to the single-port USB-C used in the new MacBook, Apple is offering a set of adapters that can convert to various conventional plugs, including VGA, HDMI, and USB 3.0 Type A, as seen currently in the MacBook Pro line. Hubs that can juggle the various connection standards and plug to USB-C will likely become a standard accessory purchase for many.

Included in Type C is a new power delivery specification, which is what allows the MacBook and Chromebook Pixel 2 to be powered through the cable. Up to 100W of power can be provided, with a maximum of 20V at 5A through a single cable. For comparison, the current MacBook Pro with Retina display 15-inch laptop takes 85W. A 24-inch LED monitor draws about 40W. A powered USB Type C hub could provide power to multiple devices, simultaneously, to the limits of household power.

Physically, the port is very small, and reversible. In size, it lies between Thunderbolt and Apple's Lightning cable. Data transfers are up to 5Gbps with Type C generation 1 as found on the new MacBook, and can be slowed to USB 2.0 speeds. For comparison, Thunderbolt 2 can push 20Gbps, and USB 3.0 Type B (commonly seen on current MacBook Pros from 2012 onwards) is also about 5Gbps. The full USB 3.1 Type C specification can push up to 10Gbps, and this may or may not be able to be added to the new MacBook and new Chromebook with a firmware update in the future. According to the spec, the connector has additional radio-frequency and electromagnetic shielding, and can handle 10,000 insertions and removals with normal force.



On the subject of power -- USB Type C includes the Power Delivery Spec 2.0, which is what regulates the direction of power. Automatically, the negotiation will flow from greater power to lesser, so a laptop should automatically power a tablet or phone. Software is possible to reverse that "flow," should the need arise, but it is unclear if Apple will allow such utilities on its hardware. "Alternate modes" are included in the new spec, allowing for use cases such as docking stations with data needs, alongside a battery power bank that can charge a laptop and similar devices.

The initial USB Type C connector isn't the end of the line for the new physical plug -- the connector has been built with "future scalability," meaning more speed and functions with no change in plug dimensions, similar to USB 1.1 to USB 2.0. Also, there may be USB 3.1 "legacy" plugs in the future, with much of the same functionality as the Type C connector, but that remains unclear at this point -- they remain in the specification, but no manufacturer has committed to the build.

No compatibility exists with power negotiation between Type C and USB 3.0 legacy. So, a USB 3.0 hub with legacy connectors won't be able to power a Type C device at full power, even with proper adapters, but it will be able to transfer data. This is why a USB Type C hub would be needed for the most flexibility with the new Chromebook and the new MacBook.



Apple's USB C video adapters are rudimentary and inflexible Type C switches. Before the year is out, the standard will be more widespread, including power negotiation, which will allow for Thunderbolt-esque hubs with multiple connection points, including a single power and data cable to a MacBook. These hubs will allow for not only USB Type C devices at full power with one charging the connected MacBook, but with either integrated USB 3.0 legacy ports or adapter cables, the use of older gear, with the lower-specced connector.

Thunderbolt, like FireWire before it, won't be eradicated by USB-C, and will exist in parallel for some time to come. Lightning is very similar to Type C, and will also continue to exist, as the physical connector and support gear is smaller than Type C, allowing for mobile devices to be thinner than those sporting the Type C connector.

Type C, when fully implemented at its full 10gbps speed, is the promise that Mac users were made alongside the advent of the dual-processor G4 -- of a single cable providing power, video, and USB, all well-integrated and more universal than the relatively ancient ADC connector we ended up with. Its sad that MagSafe is gone, but we suspect this is because the OS doesn't care much for a data source that could be connected to the power line "casually" being knocked off by a disconnect. This all said, USB Type C is the vanguard of new USB speed and potential for users. When it comes to the new MacBook, any perceived issues users may have with the connector comes as a result of Apple's decision to only include one of them -- not with the port itself.
( Last edited by NewsPoster; Mar 17, 2015 at 05:04 PM. )
     
jwdsail
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Mar 17, 2015, 07:45 PM
 
I'd still prefer MagSafe and Thunderbolt..


apple.com/feedback
     
prl99
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Mar 17, 2015, 08:00 PM
 
I like the fact that Apple's adapters include a pass-thru USB-C port with USB 3 old style along with the desired port, HDMI or VGA. This creates a small hub, something I haven't read about on previous discussions. I presume you could daisy-chain the HDMI and VGA adapters ending up with two USC 3 ports for legacy peripherals. When a legacy USB 2 device is attached does that slow the entire USB system down, causing possible slowdown in the HDMI communications as well? Is HDMI anywhere near 5Gbps? If not it should be a big deal.
     
prl99
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Mar 17, 2015, 09:36 PM
 
@jwdsail I understand MacSafe but how often do you keep your laptop connected to the power supply? If you say all the time, then you're ruining your battery. Thunderbolt (at least its speed) would be nice but I don't see this version of the MacBook being powerful enough to benefit from the speed of Thunderbolt. How many TB peripherals do you own? If you say an external disk with a single 7200rpm HDD in it then you're wasting the speed of TB anyway and USB 3 would be fine. If we were talking about a 2-3GHz quad i7 laptop, then I would agree with wanting TB but I can't see wasting the manufacturing money on TB in this MacBook.
     
Charles Martin
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Mar 17, 2015, 09:52 PM
 
I agree that Apple are clearly trying to make clearer the distinction between "consumer" notebooks and "pro" equipment. I do agree with jwdsail that a Magsafe port would have been nice, both for the protection it brings when someone trips over the cord (though this MacBook is so light I'm not sure Magsafe offers as much protection as it does for a MBP) and for saving me needing an adapter to use the thing at home, where I would want to both charge it up and attach a second display. I have no problem with the one port for transfers and video, but a separate Magsafe (which is still a better invention than anything I've seen on the Windows side) would have been even nicer IMO.

Still, if Apple didn't push us all forward, who would?
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cacruden
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Mar 18, 2015, 12:59 AM
 
I read through some documentation and from what I can tell (which could be wrong since I am not an engineer):

The current Macbook supports USB 3.1 Rev 1 Type C connector. USB 3.1 rev 1 in this case is actually USB 3.0, they renamed it for "consistency" but ended up totally confusing the situation. (5 Gbps)

Once chipsets are deployed that changes to support the actual USB 3.1 standard the equivalent would be USB 3.1 Rev 2 Type C connector which will support 10 Gbps.

Understand that this is a combination of standards:
USB 3.0 (which is now called USB 3.1 revision 1 - is a 5Gbps datastream).
USB 3.1 (which is now called USB 3.1 revision 2 - is a 10Gbps datastream).

USB-C is just the connector type itself, a Type C connector with 24 pins. Some lanes for USB 2.0 (slow), some lanes for power distribution, some lanes for high speed data that can transmit alternate data formats natively without encapsulating them on top of USB data standards. One such is display port data stream (up to 4 lanes).

I have read that the C connector itself supports up to 20Gbps (future), and I have read the new macbook supports DisplayPort 1.2 natively -- which has a much higher bandwidth than 5Gbps which makes me think that yes, the current USB data stream is limited to 5Gbps but when you connect up the displayport it may support higher speeds than the USB data stream.

It then crossed my mind that the reference of 20Gbps aligns with 4 high speed date lines for Thunderbolt. Also thunderbolt 3 supports up to 100 watts of power (like USB-C power). Other than the power and the 4 lanes of data, the rest of the Thunderbolt pinout seems to be all grounds.

Add that with Apple being involved with defining the standard and I have a sneaking suspicion that come the fall that the next "alternate data stream" supported will be the Thunderbolt data stream using a USB-C connector.

Of course Thunderbolt 3 will support up to 40Gbps data (not sure if the USB-C will do that or peak out at 20Gbps).

I suspect the omission of Thunderbolt on the Macbook was just because of power concerns and the lack of space for Thunderbolt chipsets. It was a compromise not based on the port itself.

Here is what I expect in the fall once Skylake is released. The Macbook Pro / Macbook air lines will be refreshed. The magsafe power will be replaced with USB-C (common charger standard - based on jumping ahead of pending legislation in Europe mandating a common charger standard across a wide variety of devices). This USB-C connectors (along with a few others) will be able to support any one of a number of data streams INCLUDING Thunderbolt. The USB 3.1 Rev 1/2 data stream will go up to a maximum of 5 or 10 Gbps, but the Thunderbolt data stream will reach 20Gbps (possibly 40 Gbps) along with being lower latency since it is a native thunderbolt data stream.



What this means is you can have a cable that is a USB-C to Displayport cable and connect up and existing displayport monitor.

Or

You could connect up an existing thunderbolt device using a Thunderbolt cable -> USB-C connector. It would have EXACTLY the same performance as if you had plugged into one of the older thunderbolt ports....

Or

You could connect up an existing USB device and an existing Thunderbolt device using a USB/Thunderbolt dongle (though maybe dropping back to a lower maximum data depending on how many data lanes are allocated for USB and how many for Thunderbolt).

Assuming my theory is correct (and there is enough data lanes) you could have 3 (or more if the chipsets support it) USB-C ports on the side of a laptop and plug in any combination of USB / Thunderbolt / Displayport / HDMI / or charger devices.....

In other words, the Thunderbolt standard is not being replaced by USB-C but they are merging support for many different standards into one connector.
     
Grendelmon
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Mar 18, 2015, 09:27 AM
 
What amazes me is how obsessed Apple has become with sacrificing functionality for the aesthetics of their products. Yet these same products will be connected to clumsy and cumbersome dongles and adapters to connect the everyday devices that people need and use. How elegant does THAT look?
     
Grendelmon
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Mar 18, 2015, 09:31 AM
 
Originally Posted by prl99 View Post
@jwdsail I understand MacSafe but how often do you keep your laptop connected to the power supply? If you say all the time, then you're ruining your battery
I'm not sure that's entirely accurate. Can you back that up with a citation?
     
MitchIves
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Mar 18, 2015, 09:35 AM
 
If it had two of these ports, there would be a lot less unhappy people, but I'm sure that is being saved for the MBP and possibly the Air...
     
DiabloConQueso
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Mar 18, 2015, 09:37 AM
 
If clunky dongles and adapters are a major concern, then this isn't the laptop for you (but it is for me, who rarely connects anything to my laptop save for the power cable, and favors portability over lugging a desktop replacement around with me).

That's why Apple makes no fewer than 5 other laptops (Air 11, Air 13, Pro 13, Pro 13 Retina, Pro 15 Retina) that meet your "I don't want to use dongles" requirement to varying degrees.
     
cacruden
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Mar 18, 2015, 09:37 AM
 
@Grendelmon - for an ultraportable.... I think the dongle issue is overblown for most. I don't see people plugging in a lot of devices into their laptops (and definitely not their iPads) while they are using them in any other location than home or potentially office. Walk into a University class, or Starbucks or restaurant where someone is using their portable as a portable ... and I see virtually no devices connected up. At home -- people might plug in an external hard drive, keyboard and mouse? (I thought everyone went wireless for those), USB drive - usually only to copy or backup some files. External monitor at home... yes. If you are doing that you are better off getting a dock and leaving it at home or at the office (I usually leave the charger at home and one in the office). It is not for everyone, but it is for a large audience of students, starbuck narcissists, etc. It obviously won't be great for people that do video editing or run something like VMWare / WIndows (only having two cores) but for the majority that use it for email, surfing, editing word documents, spreadsheets and coding small projects (students) it is more than sufficient (especially with the 8GB memory and high speed SSD which have probably more impact on performance for CPU non-intensive tasks). If it is not you, there are plenty of others that it is for.
     
benj
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Mar 18, 2015, 09:47 AM
 
I know users who specify laptops with tons of ports and builtins (dvd) who would get by fine with the Macbook. My only gripe is that some folks need ethernet and that does make for some ugly dongling. In fact Apples choices fro USB-C aren't that great. Hey it's one thing to create new ports but it's another to leave better implementation to "developer Opportunity"At least with Firewire apple included a fw cable so you could connect those Sony Cameras... here's Apple's USB lineup:http://store.apple.com/us/search/USB-C
"Merrily, we roll along."
     
Grendelmon
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Mar 18, 2015, 09:50 AM
 
Originally Posted by DiabloConQueso View Post
If clunky dongles and adapters are a major concern, then this isn't the laptop for you (but it is for me, who rarely connects anything to my laptop save for the power cable, and favors portability over lugging a desktop replacement around with me).

That's why Apple makes no fewer than 5 other laptops (Air 11, Air 13, Pro 13, Pro 13 Retina, Pro 15 Retina) that meet your "I don't want to use dongles" requirement to varying degrees.
Perhaps. And I suppose it's all about perspective. My two biggest concerns about any product that I buy are quality and value. I cannot justify paying that much for a "premium" laptop that lacks so much built-in functionality, especially when their true ultrabook, the Air, costs $400 less and includes so much more.
     
Grendelmon
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Mar 18, 2015, 09:57 AM
 
Originally Posted by cacruden View Post
@Grendelmon - for an ultraportable.... I think the dongle issue is overblown for most. I don't see people plugging in a lot of devices into their laptops (and definitely not their iPads) while they are using them in any other location than home or potentially office. Walk into a University class, or Starbucks or restaurant where someone is using their portable as a portable ... and I see virtually no devices connected up. At home -- people might plug in an external hard drive, keyboard and mouse? (I thought everyone went wireless for those), USB drive - usually only to copy or backup some files. External monitor at home... yes. If you are doing that you are better off getting a dock and leaving it at home or at the office (I usually leave the charger at home and one in the office). It is not for everyone, but it is for a large audience of students, starbuck narcissists, etc. It obviously won't be great for people that do video editing or run something like VMWare / WIndows (only having two cores) but for the majority that use it for email, surfing, editing word documents, spreadsheets and coding small projects (students) it is more than sufficient (especially with the 8GB memory and high speed SSD which have probably more impact on performance for CPU non-intensive tasks). If it is not you, there are plenty of others that it is for.
You do make good points. I don't use my portable to surf while drinking coffee at Starbucks, but to travel from office location to office location. I travel quite a bit. And using a MacBook would just increase my baggage weight.
     
cacruden
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Mar 18, 2015, 10:02 AM
 
About macbook air containing so much more - yes and no.
If you added 4GB of memory for a total of 8GB and take 256GB SSD option on the macbook air... there would be a difference of $100 which could be attributed to the retina display. I do expect in the fall that they might come in with one with 4GB memory and 128GB SSD like macbook air for $999 once thing settle down.... but to say that there is a huge gap on pricing ... not as much as it initially looks like.

About USB 3.1 Rev 1 Type C - There is a large number of devices in the queue for release within the first few months. It is an open standard - which will be widely supported on a lot of new devices. At least 3 docks. Apple and Chromebook being some of the first (I think there is one more), but as the next version of computers are released you will start seeing other suppliers having at least one port (and maybe more). The laptop has not even started shipping yet.
     
jwdsail
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Mar 18, 2015, 01:19 PM
 
@prl99 - Re: MagSafe - I, and the vast majority of my customers, leave their laptops plugged in often enough, that the higher risk of accidental damage seems to be a major downgrade.

Just this past week, I was visiting a customer, mostly Mac-based. They had a guest, with a HP laptop, plugged in while giving a presentation. Employee stepped over the cord, not really paying too much attention, expecting it to be MagSafe, and not a big deal if there was a snag. HP laptop ended up on the floor, not good.

There will need to be allot of re-education of Mac users (and their friends, family, roommates, cats) that will just expect that a new Mac laptop will have MagSafe, or I suspect that there will be allot of new MacBooks landing on the ground.

Re; Thunderbolt, I'm sorry, I just prefer the more flexible option. Speed is great, yes, but TB is also more flexible in what it can be adapted to. Can't imagine anyone wouldn't prefer the most flexible, and yes, fast, option on a computer with only one port, especially a computer costing this much, with just one port.

I could see maybe paying $1200 for a MacBook like this with MagSafe and TB2. USB-only? Can't see buying it at any price.. It's far too much of a compromise. It's not just form over function, is using form as a lazy excuse to remove basic function.

If others see this as a great option, more power to them. I just don't see it.

Maybe I'm just getting old?

Git off my lawn!

Meh, maybe.
     
Charles Martin
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Mar 18, 2015, 05:34 PM
 
jwdsail: as my colleague Mike is quick to point out, this MacBook isn't aimed at you, but I don't think that's a sign of getting old. Notebook use has evolved, and the same people that made the MacBook Air -- which originally had very few ports and was "underpowered" compared to the MacBook it replaced -- Apple's best-selling notebook will likely do the same for this one.

I'm expecting (no insider info here, just a guess) a new 15-inch MacBook Pro on or just before WWDC that may well be a big redesign -- inheriting many of the good things from the MacBook (lighter, 2x PCIe storage, Force Touch, etc) with more ports, magsafe, 5K video capability and more stuff for us "power users." This will help distinguish the markets for the MacBook and Air away from the serious Pro line, which would probably benefit buyers as well.
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cacruden
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Mar 19, 2015, 12:26 AM
 
I think @Charles Martin is mostly correct, the only thing I think may not be correct is the magsafe connector... which I think will be replaced to USB-C as to be ahead of pending European legislation on common chargers. I "could" see Apple being innovative and combining both USB-C and charger magsafe in a special charger cable that acts like a magsafe at the back of the USB-C casing (thereby allowing common connectors and specialized chargers). I could also see them supporting both a USB charger and inductive charger.

I could see the next macbook pro being thinner, closer to a slightly larger macbook air. I could even see the macbook air line being merged into one "pro" line that has a very wide range. I can also see them coming in with a macbook that falls just below $999 price point that is more in line with the macbook air minimum specs (4GB/128GB/low res&highres).

I expect the macbook pro (highest end) to have at least 3 USB-C connectors, 2 of which at least can handle Thunderbolt as an alternate stream (maybe even 4 connectors) - the connectors are very small.

I expect the low end macbook to have the power of the low end macbook air performance-wise even with the core-m processor (I have seen test results that indicate both that it is close to the macbook pro air - with different strengths and weaknesses; and it being a little wider.... but then these tests are dependant typically on other OS software, and other power utilities which change the performance profile in ways that the OS X operating system may handle differently (Apple invested a lot of work in power profiles and efficiency in the last few revisions of OS X).

Once all of the lines have been completely refreshed with Skylake (probably all this year - including the newly released) I think you will be looking at an amazing portable line that will be attractive to a good percentage of iPad users (that really want easy copy/paste and keyboard/mouse along with an ultralight simple device) and power users and a number of new users.

I expect by the end of the first year, macbook purchasers will outnumber all other mac sales. I am also expecting a surge in the mac users due to iPad and other tablet users being attracted to the new macbook.

As a developer, a surge in the overall number of peoples using your preferred development environment - exciting...
     
Grendelmon
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Mar 23, 2015, 11:29 AM
 
     
Ham Sandwich
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Mar 23, 2015, 11:45 AM
 
Originally Posted by jwdsail View Post
@prl99 - Re: MagSafe - I, and the vast majority of my customers, leave their laptops plugged in often enough, that the higher risk of accidental damage seems to be a major downgrade.
But what about on the Macbook, is the other end of the power connector that goes into the outlet a MagSafe-type connector? Apple doesn't seem to show what the power brick or its connectors look like.
     
   
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