Haruka's Diary
Chasing After Rainbows: 716th post - Seperating the confusion with USB type-C and 3.1

18 October 2015

716th post - Seperating the confusion with USB type-C and 3.1

When I look around YouTube comments in videos, particularly that of the 2015 MacBook, people seemed confused that the two USB type-C and 3.1 are together, or an Apple-only standard. (In fact, Google's Chromebook Pixel and newer generation Nexus phones uses it too.)

What is USB 3.1?
Here's the confusing bit. USB 3.1 has two different versions: Gen1 and Gen2. Gen1. Gen1 is basically renamed 3.0, where maximum transfer speed is 5Gbps. Gen2 is the real new 3.1 with speeds doubled to 10Gbps.

It's not Thunderbolt 3, which uses the same USB type-C connectors with the thunderbolt logo on it, so don't expect a USB type-C to mini-DisplayPort adapter to work unless it's between Thunderbolt 3 and Thunderbolt 1/2 or DisplayPort protocols. Separately, you can have video output with just USB 3.0 3.1.

What is USB type-C?
Well, we all know what it looks like and how reversible it is, but here is the list of what is is and what it isn't.

What it is not:
  • It's a propriety standard by Apple - While Apple is among the first to introduce it and among those behind it, it's not. Do you even know what USB means?
  • USB type-C is also USB 3.1 - Not necessarily. Since type-C is designed to replace type-A and type-B (and their mini/micro variants), USB 2.0 with type-C connector is possible. USB 1.1 too, though there is no supported backward compatibility to 1.1 for 3.0 3.1 Gen1.
What is new about it over older standards:
  •  It makes using USB On-The-Go (OTG) devices less troublesome and confusing - Type-A is for host devices, type-B is for slave devices, but with portable devices like smartphones these days acting both as a host and slave this is tricky: storage device you want to connect has type-A, but host device uses micro-B. Using type-C on both ends eliminates the weird female type-A to male micro-B adapter/cable necessary to make it work.
  • Charge a device with another device instead of plugging it to the wall or PC -The concept of is not new with power banks having been around for a while, but the difference is that you can basically charge a phone with another phone. Helpful if you are running low and your friend's has more charge to spare.
  • Supports "Alternate Modes" - It supports different protocols with the same USB type-C cable where, like Thunderbolt 3 mentioned earlier, utilizes the same cable, provided the hosts supports it.
  • Supports USB Power Delivery 2.0 - Now supports up to 100W (20V 5A) of power. Older standards supported between 0.75W (5V 0.15A) and 7.5W (5V 1.5A). This means a whole new group of devices, like laptops, could just be powered from USB without the need of a separate power brick. You can use the same 100W charger to charge your phone at 5W, but don't expect your phone charger to charge your 100W device any higher than 10W (5V 2.1A).

You will need an adapter if converting to and from type-C, but as time passes by, this may not be needed as more devices come into the market.

At the time of writing, there are a few devices released with USB type-C connector, but quite rare. The common "standard" USB cables should have type-A male on one end, and type-B male on the other. the type-B end can be replaced with mini-B (deprecated in 2007) or micro-B. USB 3.0 variants of these add additional pins, but still usable with 2.0 cables without the need for adapters, though limited to 2.0 speeds due to the lack of pins needed for 3.0. A standard type-C cable should have type-C male on both ends, where anything else is non-standard. You may encounter type-C to type-A at this time, which is fairy common for any USB to non-standard USB ports like that 30-pin connector, or a particular dual-screen portable handheld device.

Micro and Mini variants of type-A do exist, but are strangely uncommon. Even though type-C is about the same size as micro-B, it is wrong to call it a micro connector. It may be possible to have an even smaller variant of type-C, but that doesn't exist at the time of writing.

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中野区, 東京都, Japan
帰国子女 英語能力は堪能。趣味はアニメや漫画やプログラムコードを編集。通常、あたしの小説を英語で書いてです。Grew up abroad &travelled to different countries. I write my own fictional novel on my blog.