The cable and connector standard known as USB is an acronym for Universal Serial Bus. Promoted by not-for-profit organization USB Implementers Forum, USB was launched in 1996 to standardize communications and electric power supply between consumer electronics and peripherals – as an example, a laptop and an external keyboard, or a smartphone and its charger. From the users' perspective, one of the most critical advances granted by the interface is self-configuration, insofar as devices communicate with minimal effort from users.
USB cables and connectors have become widely popular, largely replacing other types of ports and evolving throughout the years: newer USB versions offer more data exchange speed and enhanced power management. The Universal Serial Bus' first generation, USB 1.x, included USB versions 1.0 (1996) and 1.1 (1998). The next generation, USB 2.0 (2000), improved data transfer speeds from 12 Mbit/s to 480 Mbit/s. The following generation, USB 3.x, was developed with goals of increasing data transfer rates, reducing power consumption, and increasing power output. With a maximum data transfer rate of 5 Gbit/s, USB 3.0 was launched in late 2008, but devices equipped with the same USB generation weren't released until early 2010. Subsequent standards in the USB 3.x generation have increased data transfer rates up to 20 Gbit/s (2017), and a new generation, USB 4.x, is set to be released soon, with data transfer rates up to 40 Gbit/s.
Although there are some physical differences between USB-based connectors (USB, USB-C, and Apple's soon-to-be-defunct Lightning), the USB communications standard has become the norm in the smartphone industry. When choosing your device, a higher USB number represents a newer and, therefore, improved version.
The photography industry has also adhered to the USB communications standard. Whichever the product category, when it comes to USB, a higher number represents a newer and, therefore, improved version.