One cable to rule them all

27-04-2017 |   |  By Mark Patrick

When Apple thinks there is a better option available than current de facto connectivity standards it has never been afraid to pioneer it. It was therefore no surprise when the early 2015 MacBook launched featuring just one wired connection type (aside from the headphone jack), and a completely new one at that. There was initial concern and confusion about how a single type of connector could be sufficient for many different applications. Why was Apple one of the earliest adopters of USB Type-C, when it had nearly no device support at the time?

Apple’s decision to go all-in with USB-C helped familiarise people with the standard and legitimise the latest iteration of the USB connector. From the specifications, USB Type-C, or USB-C, is advantageous to consumer device design - with faster data transfer, better power delivery options and, importantly, the ability to do both concurrently. All of this makes USB-C much more than a normal iteration of the standard. Google and others have also seen its potential and started integrating it into their products.

The USB-C connector is similar in size to its Micro-USB predecessor. One major difference is it is completely symmetrical so it can connect both ways up, thereby removing a downside of previous USB plugs. Moreover, both ends of the USB-C cable can be the same, making them reversible (unlike earlier USB leads). This means that cabling is much easier to use.

The USB-C also offers a substantial increase in data transfer speeds, using the USB 3.1 protocol to deliver up to 10Gbps. As a result it compares much more favorably to other high-speed data protocols, such as Thunderbolt and 10 GbE networking, than earlier USB did.

It has another trick up its sleeve - advanced charging. Using the USB Power Delivery protocol, it can deliver 100W (more than adequate to charge a laptop, tablet or smartphone). Crucially, it can deliver this level of power while also transferring data. As power delivery is bidirectional, a laptop could charge a phone and then be charged itself from a power bank, using the same connector (so separate cables are no longer needed for these functions). USB-C offers five power profiles to ensure devices can be charged according to their own particular requirements. These range from 5V, 2A up to 20V, 5A.

It is difficult for any new technology to break into the mainstream. While USB-C offers huge plus points over traditional connectivity, these existing cables work, and wherever we are, usually it is easy to find one. Ubiquity of any technology can prevent uptake of new alternatives (even when there are clear operational advantages enabled by such migration). However, Apple choosing USB-C as the only wired connectivity present in the MacBook may have made the difference between widespread adoption and a good concept whose time never came.

By pushing its huge customer base down the USB-C path, Apple has created significant demand for USB-C peripherals, which device manufacturers have consequently been compelled to offer. Apple’s decision was probably the biggest reason there is now a wide variety of USB-C devices available.

The features incorporated into USB-C reflect our relationship with today’s gadgets. Wireless connectivity and multiple devices have taken over from Ethernet-linked desktop computers. One of the original uses for USB was data transfer and storage. While much of this is now done wirelessly, USB itself remains relevant, thanks to its power delivery capabilities.

The pre-USB-C generation of USB was ideal for charging mobile devices, and as such, became ubiquitous in this area. But the power it delivered was not enough for larger devices, and for those it was capable of charging, it would sometimes prove too slow. USB-C manages to take things up a notch. Higher power delivery, simultaneous data and charging capability and bidirectional charging all result in the convenience of a simple solution with less cabling and fewer adapters: perfect for users who are on the move.

The 100W power delivery from USB-C enables more power-hungry devices to share the same charging cable as smartphones, meaning almost all device classes can converge around this single connectivity protocol, in much the same way earlier phones did around Micro-USB.

The 10 Gbps data rate supported means USB-C can also be used to power and drive displays at up to 4K resolution, while still having enough spare for other data. Competing technology, such as HDMI, can’t achieve this. USB-C monitors and TVs can therefore be used as docking stations or hubs.

USB has long done what it was designed to do, connecting kit and powering certain devices. But the core technology is over 20 years old and its limitations were showing in the context of today’s devices and lifestyles. USB-C brings the standard in line with the elevated expectations of modern users. It acknowledges that USB is now as relevant for charging as transferring data (or perhaps even more so), and hence offers more power and a range of profiles for contemporary devices. At the same time, its faster data transfer rates ensure it remains viable for this as well.


By Mark Patrick

Mark joined Mouser Electronics in July 2014 having previously held senior marketing roles at RS Components. Prior to RS, Mark worked at Texas Instruments in applications support and technical sales roles. He holds a first class Honours Degree in Electronic Engineering from Coventry University.

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