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Reversible, tiny, faster: Hands-on with the USB Type-C plug

Ars chatted with some of the main actors behind the new plug that supports USB 3.1.

Reversible, tiny, faster: Hands-on with the USB Type-C plug
Megan Geuss

SAN FRANCISCO—Last week, Ars met up with several representatives of the non-profit USB Implementer's Forum (USB-IF) to check out some of the first USB Type-C connectors off the assembly lines. The Type-C specification was announced in December and finalized in August, and it's set to bring a number of improvements to its predecessors, in addition to being smaller than the Type-A USB plugs we're familiar with today.

Considering how many USB Type-A devices are still being actively built out there (over 4 billion USB-compatible products are made each year), this smaller, reversible connector represents a significant jump. Jeff Ravencraft, president and COO of USB-IF, told Ars that USB-IF wanted a connector that worked equally well for large and small devices. “We also understand that yeah the consumer maybe has some trouble with putting in that cable connector,” he added of the Type-C's new-found ability to be plugged in right-side up or upside down, like Apple's Lightning connector.

The new Type-C connector is also slightly bigger than its proprietary cousin, with Type-C sized at approximately 8.4mm by 2.6mm and Lightning coming in at 7.7 mm by 1.7 mm. Unlike the reversible Lightning, but similar to USB connectors before it, the USB Type-C connector has a mid-plate inside the receptacle that the plug surrounds when it's inserted.

A clear look at the inside of the receptacle as defined by the USB Type-C specification released in August.
Enlarge / A clear look at the inside of the receptacle as defined by the USB Type-C specification released in August.
USB-IF
One of the first USB 3.1 Type-C cables, plugs, and receptacles off the assembly line.
Enlarge / One of the first USB 3.1 Type-C cables, plugs, and receptacles off the assembly line.
Megan Geuss

What it can do

The new so-called “SuperSpeed” USB 3.1 standard will deliver a maximum 10Gbps when transferring data, which is twice the speed promised in USB 3.0, but not nearly as fast as the 20Gbps promised by Thunderbolt 2, which just started showing up late last year. Still, Ravencraft said that USB 3.1 would be capable of driving 4K displays and would be able to deliver data and power simultaneously.

On the power-side, USB-IF announced its USB Power Delivery v2.0 spec last week. The new connector will continue to deliver 100W of power, but it will allow the voltage, current, and direction of the power flow to be negotiated so that the source of power delivery can be switched without the need to change the direction of the cable. That means a phone could provide power to a tablet and vice versa.

USB 3.1 Type-C connectors will also be able to support alternate modes (PDF) with a USB Billboard Device Class specification, which defines how devices connected by USB should talk if an alternate mode is enabled. Individual manufacturers or standards organizations will be able to develop their own alternate modes after obtaining a standard or vendor ID (SVID) from USB-IF. “One example of an Alternate Mode is PCIe,” a spokesperson from USB-IF told Ars. “In a docking station, for example, a device would use its USB Type-C connector to make a connection when placed in a cradle dock. If the manufacturer has enabled a PCIe Alternate Mode on the USB Type-C connector, then the user could use PCIe to connect additional dock functions, such as a network controller.”

With alternate modes, USB-IF members told Ars that the organization is looking for ways to signal easily to consumers what an alternate-mode-enabled device does. “We want the consumer to very easily look at the port and know what they’re getting,” Ravencraft told Ars.

A side view.
Enlarge / A side view.
Megan Geuss

The new USB 3.1 Type-C connectors are supposed to be durable for 10,000 cycles, and USB-IF says it has improved electromagnetic interference (EMI) and radio-frequency interference (RFI) mitigation features in the specifications. Finally, UBS-IF also showed Ars a demo of wireless connectivity over USB, something that's been long in the making but has only just now become a reality. That function is "designed to allow wireless devices and docking stations to communicate over the USB protocol, without the need for a physical USB connection."

Way of the future

One problem new standards often face is that it's hard to spur widespread adoption of the new standard if the old standard works okay. But USB's ubiquity in the market gives Type-C connectors a leg up to becoming integrated into the plug pantheon. USB-IF itself is made up of many engineers whose day jobs are at big tech companies like Intel, Microsoft, Broadcom, Hewlett-Packard, Nokia, Nvidia, NXP, and Texas Instruments, to name a few, so at least a handful of employees at those companies have an impetus to push Type-C.

At our meeting last week, Ravencraft and his associates, Brad Saunders, a USB 3.0 Promoter Group Chairman, and Rahman Ismail, the USB-IF CTO, (both of whom work for Intel by day) told Ars that a number of device manufacturers are preparing to launch products in early 2015 that will have USB 3.1 Type-C plugs. “Some people are trying to get things out before the end of the year, but I can’t say who,” Saunders told Ars. “Clearly people who’ve been working on the spec for over a year” would be good to bet on, he added.

So it all seems great right? New products will adopt the new standard, and as older devices get retired, USB 2.0 will go the way of the VGA cable. Still, Ars had to ask if there were trade-offs in building the Type-C connector—it's faster, it does more things, but usually there are challenges, or something has to give, to make the improvement happen. Saunders fielded that question: he said that mobile device manufacturers involved with developing the spec originally pushed for something smaller, like the micro USB, but USB-IF as a whole wanted a connector that could power a huge display and a tiny phone equally well. “There weren’t a lot [of trade-offs] originally. The target for the spec was to make it as small as the micro USB, but in the end we made it as small as possible, and we’re still about 10-15 percent away from that goal,” he said.

The new Type-C connector is small, but not as small as micro USB. It makes up for that extra size in power, though.
Enlarge / The new Type-C connector is small, but not as small as micro USB. It makes up for that extra size in power, though.
Megan Geuss

Nevertheless, “The OEMs understood the value of the performance and the improvement in rigidity and durability,” Saunders added.

The Type-C's famed reversibility is, in itself, a trade-off, too, because without reversibility, the plug could have been even smaller. “A reversible connector takes more gates, more silicon to do it, and when you bring a new technology [to the assembly line] if you have to design a bunch of new silicon, that’s pretty significant. But in the long run the user will get a better experience,” Saunders told Ars.

Saunders, Ravencraft, and Ismail were quick to point out that USB-IF still supports its earlier USB versions. “I think the neat thing is that the consumer has never really lost out on their investment on any USB product,” Ravencraft said. “People love USB because it just works. It's a safe investment and it works with everything.”

“We make the standards available and then it's really up to the market and what the market's going to bear,” Ravencraft told Ars. Saunders chimed in, “the Type-C connector is the closest we’ve come to obsoleting technology. But in the transition you’ll still see Type-C to Type-A connectors.”

With the announcement of the Type-C connector, USB-IF also acknowledged that the future changes quickly, and USB 3.1 Type-C may look like a dinosaur in due time. With respect to that problem, the Implimenter's Forum said that it designed the Type-C connector with “future scalability” in mind. “The USB Type-C receptacle, plug, and cable designs are intended to support those future enhancements without modification,” a spokesperson for USB-IF told Ars. “As such, consideration was given to frequency scaling performance, pin-out arrangement, and the configuration mechanisms when developing this solution.”

”The definition of future USB performance enhancements is not in the scope of this specification but will be provided in future releases,” the spokesperson added.

Channel Ars Technica