Mark Pickavance explains the new USB Type C connector, and the changes that its arrival will usher in
It’s easy to forget that USB had remarkably humble and generally inauspicious beginnings. I remember first getting an adapter and a small collection of USB 1.0 devices; they worked some of the time, but often they’d crash Windows. At that point the remit of this connection technology only really extended as far as mice, keyboards and printers, as it wasn’t fast enough for much else. However, what it lacked in speed it made up for in the simplicity of the connection and the thin cables, which were a revelation to anyone familiar with parallel printer connections.
USB 1.1 was much better, and when USB 2.0 appeared the possible uses of this technology blossomed to encompass all manner of external devices. There were still issues when using it for high bandwidth devices, like drives, though – and the amount of power that a device could pull from the computer was limited.
USB 3.0 addressed the bandwidth problem, and also at this time USB 2.0 Micro-B became the connection of choice for all but Apple-made smartphones. Now USB 3.1 is about to add even more bandwidth, we’re told – so what is the USB Type-C connector, and how does it fit into the bigger picture?
USB Over Time
For those interested in the history of USB, there have been no less than eight different connector types up to this point. Part of the reason for this proliferation of plugs is that the host and client have used different designs at their respective ends, as the cables aren’t reversible. Also to maintain a degree of compatibility many of the connectors are variations on their predecessors. So, for example, USB 2.0 Micro-B is a design refinement of of USB 2.0 Mini-B, while USB 3.0 Micro-B adds extra pins to the USB 2.0 Micro-B design. The problem with adding extra bits in this fashion is that it’s not fully inclusive, because try as you might, you can’t put a USB 3.0 Micro-B cable into a USB 2.0 Micro-B receptacle. Thus, you can’t realistically keep simply adding extra elements to a connector.
Therefore, those behind USB decided they’d bite the bullet and introduce a totally new connector that would hopefully banish all the others once it became established. It’s to be known as USB 3.1 Type-C, but it’s critical to understand that it was developed in isolation to USB 3.1 standard, which can operate on the existing USB 3.0 connectors. What USB Type-C actually does is provide the optimal situation to use USB 3.1; it is also very easy to differentiate the sockets, as they’re not just coloured differently but physically incompatible.
Let’s look as the new features of USB Type-C and see how they bring USB fully into the 21st century.
Enhancements
The first thing that you notice about USB Type-C is that the host and client connectors are identical, because the cable is fully reversible. That will make the cables easier and theoretically cheaper to make, and cabling very straightforward.
In addition to being the same at both ends, the connector is also symmetrical and reversible in orientation, so you can force it in the ‘wrong’ way up! These points alone offer a major improvement over USB in general, but specifically Micro-B on phones – as it’s currently easy to push a Micro-B cable into its receptacle on a Smartphone inverted, and damage either the cable or the phone. Once they are damaged, a perfectly good phone in other respects can’t be charged up, until it has a Qi pad power capability.
Beyond this, there there are some other great features. With the standardisation of USB Micro-B on phones, the expansion of USB into changing and powering devices has exploded. Now, most phones and tablets – unless their made Apple – charge directly using this connector.
The problem with this usage is that the batteries in these devices are getting larger, and charging them with a potential cap of 9W takes progressively longer. Some companies have tweaked adapters to deliver more power over USB, but there isn’t going to be a point where you could use Micro-B to charge a laptop, for example.
Type-C fixes this with 20V and 5A power provision, allowing up to 100 watts of power over the new connector. That’s enough power for most laptops and the foreseeable future requirements of phones and tablets. But, and this is a great ideal, under all the other USB power systems the power would run only from the host to the peripheral, but on this system it runs both ways.
The implications of this are significant. As it turns the charging socket into a USB peripheral socket on any devices that uses it. Also, imagine that you’re trying to complete an important message on your phone away from mains power, and it’s about to drain out. You could simply hook up your laptop, and charge it, or vice versa. That’s useful, and the sort of interchangeability that people generally love, even if they don’t have any immediate use for it.
The final must-have feature of USB Type-C is one that it automatically inherits from USB 3.1 – namely, 10Gbps of bandwidth. That’s enough to support an external drive at more than a gigabyte per second, or display a 4K image on a monitor though DisplayPort, or handle multiple gigabit LAN connections.
If you thought USB 3.0 was good, then the double performance offered by 3.1 should excite you, and the majority of 3.1 devices should use the Type-C connector.
However, there are always a few caveats that need to be outlined along with the all the advantages we’ve highlighted.
Not All Good News
The most obvious problem come with the vast collection of existing USB hardware that was dreamt up before long before Type-C was even conceived. That means should Type-C become popular we’ll be stuck with using tiny adapter cables so we can plug our old phone or peripheral into our latest kit.
This was highlighted by Apple, which launched one of the first machines to feature USB Type-C. However, it deigned to give its new MacBook just one USB-C port and no legacy connectivity. Most computer makers aren’t that daft/presumptious, though, and I suspect that we’ll see USB Type-A and Type-C living together for some time on most computers.
Thankfully the use of Mini-A and Mini-B has almost died out, and Micro-A wasn’t ever that popular. That leaves the adapters you might want as Type-B to Type-C and Type-A to Type-C, and possibly Micro-B to Type-C. If you use USB 3.0 peripherals you also might need those specific converters, under some circumstances.
What is quite clear from the Type-C specifications is that no adapters will be allowed to include a USB Type-C receptacle, only the male connector.
There is also another aspect of Type-C that might not be very desirable, and that’s the increased number of wires.
USB 1.x and 2.0 used just four wires, in that it had 5V power, two data lines and a ground line. This expanded to five wires under the mini and micro layouts. USB 3.0 increased that by another five to ten wires by adding four more data lines and another ground line. And, now USB Type-C (USB 3.1) adds a further five wires, to make 15, plus a braid over 24 pins, so that it can toggle cable orientation and to handle power management.
That last aspect is likely to make the cables less cheap, because USB power Delivery 2.0 specification requires that each cable contain a chip with an ID function making them an active component in the data and power chain. This level of sophistication might well make these cables thicker, less reliable and more prone to damage, but we’ll see how that pans out over time and in-the-field use.
As with most things in the world of computing, it might be best to let others test these waters before diving in yourself. This will also mean that early adopters can suffer the expense of the cables, before the prices inevitably rationalise further downstream.
Success Or Failure?
What’s probably the most annoying aspect of USB-C, other than it failing to appear before USB Micro-B became so popular, is that it is almost certainly destined to succeed despite these obvious snags. It will be a generally irritating translation, and one that will inevitably take longer than it reasonably should, but we’re pretty confident that eventually we’ll simply refer to one kind of USB, and connecting devices will become better because of that.
The new design not only solves the insertion damage issues, but also the increasing use of USB as a power delivery technology. And unless we suddenly decide that 100 watts isn’t enough power and 10Gbps is insufficiently fast data transfer, it should suffice for some time to come.
However, if the last 30 or more years of computing has taught us anything, it’s that every dog has its day – and Type-C will be replaced with Type-D and Type-E eventually, for whatever technical and commercial reasons. Indeed, there is a fine irony in all the ‘future proofing’ comments that Apple made about Thunderbolt, only to produce a machine that includes USB Type-C and nothing else within a few short years. It appears the only conclusion to be drawn from this is that the future doesn’t exclusively contain only those technologies you’ve backed, even if you’re all-knowing Apple.
What’s amazing about USB is that this is a technology that started first to connect low bandwidth peripherals has now encompassed not only external storage, but is now set to be the preferred power distribution and charging technology of the future. There is always a danger that USB will become of the jack of all trades and the master of none, but it has managed to do pretty well so far.
Type-C might annoy some at first, but once we’re got through that awkward phase, it could be the connector unification that all PC and mobile device owners will truly appreciate.