USB 3.0 Connectors and Receptacles Explained
The other day, I opened one of the products I received for review, and I found a blue connector on the board with no description. USB 3.0 connectors are blue this connection seemed “funny” with two internal connectors, and I though it must have been something else, and asked on Google+.
It turned out this is a USB 3.0 Standard-B receptacle. As my knowledge about USB 3.0 connectors was obviously lacking, I’ve decided to investigate and have a look at the different existing and upcoming USB 3.0 connectors that we should find in different types of devices and computers now or very soon.
This is the easy one, it looks very similar to the USB 2.0 connectors, except it’s blue and adds 5 pins for USB 3.0 connectivity. It’s backward compatible with USB 2.0, and the receptacle is used for hosts. Most people must have already seen that one.
USB 3.0 Standard-B receptacles and connectors are somewhat similar to the USB 2.0 version, but are larger, and with one extra row for USB 3.0 connectivity. Such receptacle accepts either a USB 3.0 Standard-B plug or a USB 2.0 Standard-B plug, and it’s also backward compatible with USB 2.0. Due to different size, a USB 3.0 Standard-B connector can’t be plug into a USB 2.0 Standard-B receptacle. The Standard-B receptacle is used for USB devices. If you have a USB 3.0 device (e.g. USB hard drive) you must have already seen this, but since I don’t have ny it was my first time to see this type of connector.
The USB 3.0 Micro-B cable plug consists of a standard Micro-B USB plug, with an additional 5-pin plug place on the other side. That’s been done this way for USB 3.0 Micro-A host connectors to preserved compatibility with USB 1.x/2.0 Micro USB cables. There’s no way to connect a micro USB 3.0 cable into a micro USB 2.0 receptacle due to obvious mechanical differences. I understand these types of connectors and receptacles can’t be found in many devices just yet, Samsung Galaxy Note 3 being an example, but many mobile devices may eventually feature micro-B USB 3.0 receptacles.
There’s a new type of USB 3.0 connector coming up announced last December. I could not find pictures yet, but we do know this new connector will be about the size of USB 2.0 Micro-B, it will be reversible (“users will no longer need to be concerned with plug orientation/cable direction”), support scalable power charging, and USB 3.1 Superspeed+. Since many people do not really like USB 3.0 Micro-B, USB Type-C connectors may even replace the latter in mobile devices such as tablets and smartphones.
USB 2.0 has 4 signals: Ground, Power (5V), and D-/D+ differential pair for data. There’s also the shield provided by the metal housing. USB 3.0 is backward compatible but adds Superspeed transmitter and receiver differential pairs (4-pin), and ground for signal return. According to the table below, there are also some “Powered-B” with 2 extra pins for power and ground provided by the device.
Source: Mostly Wikipedia