One USB plug to rule them all? That's sensible, but no...

Plugs that look the same, but aren't. The man in Clapham PC World not keen

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Comment It’s only taken thirty years, but we’ll soon have one plug that, on paper, does it all: power, video and all kinds of peripherals. Cue headlines about “one cable to rule them all”. And it’s reversible!

However, “soon” isn’t “now”. It’s going to be a confusing and expensive journey before the promises are fulfilled.

The last piece in the jigsaw fell into place yesterday at Computex, and cemented the USB-C socket as the winner. Intel announced that the third generation of Thunderbolt will support USB-C plugs.

So only one kind of plug is needed to support power, video and audio, and high-throughput data peripherals such as disk drives.

But that doesn’t mean one cable will support everything: there will be several different kinds of USB-C supporting different capabilities, ensuring confusion continues for some time to come.

The reason is obvious to the tech-savvy, but less so for the typical user who has wandered into PC World on a Saturday morning. The plugs may be the same, but the capabilities are defined by the gadgets at each end of it.

Since the expense is defined by the capabilities of the host controller, it all depends on how much the market-conscious manufacturer wanted to spend.

Most people who’ll see a USB-C socket won’t be getting Thunderbolt 3 performance, as the Thunderbolt hardware is a luxury-priced item that will continue to be in high-performance hardware, rather than the value mass-market.

So the industry is moving to “one plug”, but retains lots of different standards. At least in the bad old days, you knew you couldn’t plug your projector monitor into the modem port and expect it to work. It wouldn’t fit.

Right now we have two flavours of USB-C using the USB 3.x protocol: Gen 1 (5Gbps) and Gen 2 (10Gbps). Some companies throw the old USB 2 protocol through the physical USB-C connector, but we'll ignore those and focus on USB 3.x.

The USB-C spec provides a few performance tweaks: asynchronous traffic flow, smarter power management, and more throughput for power and data. At its most basic, USB-C Gen 1 is USB 3.0 renamed: it's USB 3.0 with support for the new physical plug.

Nokia’s N1 tablet conforms to this minimum: you’re getting one plug to charge the device with that also being a data port. But not much else. The host controller has a USB 3.0 feature set.

Gen 2 is where the action is, but here, capabilities are moving along parallel (no pun intended) development tracks, moving at different (no analogy intended) speeds.

USB ‘Alternate Mode’ is what gives Type-C ports the ability to support other protocols, such as DisplayPort (or Thunderbolt). This requires the co-operation of the non-USB peripheral working groups, and it’s still very early days. (Type-C itself was only announced in December).

The power capabilities of Type-C have their own working group and spec: USB Power Delivery. And there’s USB-over-radio, being pursued by two groups, the old UWB-inspired Wireless USB group, and this one. You can’t have too many computer standards, as the old joke goes. Just call them all USB.

So clear consumer labelling is going to be needed, but the personal computer industry hasn’t done a fantastic job on this in the past, even on simple transitions. USB 2.0 was High Speed, 3.0 SuperSpeed. Now the consumer in PC World will see one plug, but won’t be sure whether it will support, or not support, that particular monitor (“4K or not?”), or that particular drive or array, or be sure whether it provides enough power to charge that laptop and a phone at the same time.

Perhaps it would have been clearer to call USB Type-C “NooSB” or “Newport” (the council would be glad of the publicity) with something to label the feature set.

Even for a tech savvy user – as most of you are – it needs a bit of homework. And since many of us act as tech support for less tech savvy friends and relatives, we're going to be kept pretty busy. All hail USB. ®

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