USB Types & Standards

USB (Universal Serial Bus), is an interface for connecting a computer and peripheral devices such as a printer, digital camera, scanner etc. It is a standard connection used to connect, communicate and transfer data. A USB port on a computer or a laptop is called as a receptacle, it is a slot that is used to connect a host to other devices via the USB cable. A connector on the ends of a USB cable is called as the plug. Before starting to explore different types of USB cables, let’s first understand what are the different USB standards.

USB Standards/Version

USB 1.0 – Introduced back in the year 1996, it had a data transfer rate of 1.5 Mbit/s (Low Speed). The revised USB 1.1, released in the year 1998, had a transfer rate of 12 Mbit/s (Full Speed).

USB 2.0 – Introduced in the year 2000, it has a data transfer rate of 480 Mbit/s (i.e. 60 MB/s) and defines a High-Speed USB transfer mode. Today, every USB port you see will support at least USB 2.0 if not USB 3.0 or USB 3.1. Although this is faster than the previous USB 1.1 standard, it is still much slower than what USB 3.1 Gen 1 (USB 3.0) and USB 3.1 Gen 2 offers.

USB 3.1 Gen 1 (USB 3.0) – Introduced in the year 2008, it supports a data transfer rate of 5 Gbit/s (i.e. 0.6 GB/s or 625 MB/s) and defines a SuperSpeed USB transfer mode. It performs 10x faster and better than the previous USB 2.0 standard in terms of performance and power management.

USB 3.1 Gen 2 – Introduced in the year 2013, it supports a data transfer rate of 10 Gbit/s (i.e. 1.25 GB/s or 1250 MB/s) and defines a SuperSpeed+ USB transfer mode. It delivers double the speed of USB 3.1 Gen 1. This is the latest and the fastest USB standard out there currently (at the time of writing this article). It is backward compatible with USB 3.1 Gen 1 (USB 3.0) and USB 2.0.

However, to practically achieve a maximum data transfer rate, all the USB ports and cable types must be of same USB standard/version.

USB Types & Standards

USB Connectors (Types)

A cable with USB 2.0 or 3.0 standard refers to the speed and performance of the cable, whereas a USB type-A or a USB type-B refers to a physical shape of a connector.

Consider an example of a USB cable used to connect a computer and a printer, the end of the cable plugged into the computer is called a Type-A (rectangular shaped) connector and the other end plugged into the printer is called a Type-B (square shaped) connector.

The connectors on the ends of a USB cable are a USB Type-A and Type-B male connectors while the USB ports on a computer and peripheral devices are USB Type-A and Type-B female connectors.

Next, there are two ways you can recognize USB 3.0 ports and cables. A USB 3.0 ports and cables have a blue coating inside their plug and receptacles.

Another way to identify a USB 3.0 port and cable is by observing the symbol. It’ll be beside the ports and over the cable.

The symbol on the left refers to USB 3.1 Gen 1 (USB 3.0). The one on the right refers to USB 3.1 Gen 2.

Now the latest plug design that’s starting to grab attention is the USB Type-C (USB-C) connector. Just like USB Type-A and Type-B, USB-C is also compatible with USB 3.0/3.1.
This newest plug design is starting to become popular because of number of things, such as

  1. Size – It is a tiny connector roughly the size of a micro-USB. It is smaller than the Type-A and Type-B connectors.
  2. Data Transfer – Since it is USB 3.1 compatible it can support a data transferring rate of 10 Gbit/s (i.e. 1.25 GB/s).
  3. Power – It can carry up to 100 watts of power, usually a laptop consumes about 30-60 watts of power. So this USB Type-C ports are capable of charging a laptop.
  4. Reversible – It is backward compatible with USB Type-A and Type-B connectors. It is reversible, meaning you can hold it anyway and it’ll fit in the first try, every time, unlike Type-A connectors.


USB-C cable has Type-C plugs present at both ends. It’s gaining adoption because those massive USB Type-A and B ports just don’t fit in smaller and thinner devices. Currently, USB-C is in the transition phase, as there are too many computers and peripheral devices that support only USB Type-A and Type-B receptacles and plugs, to adopt USB-C completely. For now, connecting USB-C devices to USB Type-A or Type-B compatible devices can be done by using different adapters.

Some of the devices that support USB-C are Apple’s 2015 12-inch MacBook, 2016 13-inch, and 15-inch MacBook Pro, Chromebook Pixel; smartphones such as Samsung Galaxy Note 7, Huawei Nexus 6P, LG Nexus 5X and headphones such as the JBL Reflect Aware C, and SanDisk Ultra flash drive to name a few.

USB Types & Standards

Due to its tiny size, high power delivery and data transfer rates, it’ll most likely replace all the different ports across all the devices. There will be only one type of port for all the necessities such as charging, transferring data from flash drive, connecting peripherals and even connecting headphones.