Universal Serial Bus (USB) on smartphones is an industry standard that establishes the specifications for cables and connectors. It is also used for protocols for connection, communication, and power supply interfacing between computers, smartphones, and other peripherals.

Universal Serial Bus USB on smartphones
(Image credit: Wikipedia)

USB was designed by Compaq, DEC, IBM, Intel, Microsoft, NEC, and Nortel in 1996. Before USB, different equipment manufacturers designed their ports. These ports could only connect to their proprietary peripherals. This made it a headache for consumers, as keeping track of which connector cable or charger type to buy was rather difficult.

This was very true in the old days as Nokia phones had big pin and small pin chargers. Sagem had theirs as did Samsung and the others. All of these different cables and chargers were incompatible with one another. Funnily enough, if I remember correctly, what is known as a micro USB cable was once referred to by many Nigerians as “the Blackberry charger”😂😂.


The adoption of the Universal Serial Bus standard (USB) on smartphones solved this problem. It did this by not only standardizing connection between devices but by also supplying charging power at the same time, killing two birds with one stone. Apart from Apple which uses a proprietary connector called “lightning”, all android devices fully conform to the USB standard. This has made procuring, sharing, or swapping USB cords and chargers between consumers very easy.

Functions of a USB

A USB system acts as an interface between two connected devices. It ensures the devices remain connected and that both devices are compatible and work well together. USB consists of a host and one (or more) downstream ports (USB devices).

When two devices are connected (tethered) to each other via USB, they form a closed system called a bus. USB operates a slave/master architecture with a host and receiver. The host acts as the master/controller of the bus while the USB device acts as the slave subject to the control of the host.

USB is used to connect Personal Computers (Desktop) and Laptops. PCs can also use USBs to connect to smartphones. Smartphones can also be connected as well as keyboards, mice, cameras, printers, modems, disk drives, etc.


USB Type A

These connectors are extremely common. They can be found on one end of almost every USB cable these days. Type A cables are used to connect various devices such as smartphones, cameras, keyboards, and so forth to computers. They can also plug into wall chargers used for charging our gadgets.

Universal serial bus USB type A

USB Type B:

USB type B cables are not quite as common and versatile as the others in this list. They are primarily used to connect printers and scanners to computers. They have a square shape with beveled exterior corners on the top ends. Although they are still used today, USB Type-B connectors are being slowly phased out.


This was the standard for various devices a while back but has been phased out for the most part and replaced by the micro-USB connector described below. You’ll find it on older models of various gadgets especially cameras, MP3 players, and game controllers, among others. As its name suggests, it’s smaller than a regular USB, but larger when compared to its successor.


The micro-USB

This connector is very small and allowed manufacturers to start producing slimmer devices. Although it’s being phased out by USB Type-C described below, micro-USB is still the most common port found on most smartphones, tablets, and other devices today. It has been adopted by almost every manufacturer around the globe, except Apple and maybe a few other companies.

USB (type) C:

This is the latest USB port that’s found on newer smartphones and other mobile devices. It offers faster data transfer rates than previous USB versions. The biggest advantage of USB-C is that, unlike its predecessor, it’s reversible. This means it can be plugged in either up or down. It has become the new standard for mobile devices.

However, some manufacturers are still releasing new handsets with older micro-USB ports, particularly in the affordable segments. USB-C is an emerging standard that has lots of promise. It’s smaller, reversible, and fast. USB-C can both receive and provide a lot more power than previous versions of USB. Apple’s MacBook line only has a single USB-C port, with the new MacBook Pros packing several ports.

Aside from data transfer, USB-C can also power devices, output display to a monitor, and more. Unlike USB-A, cables with USB-C connectors on both ends are standard and allow full utilization of its powers. However, USB-C to USB-A cables are also common, allowing for compatibility with older devices.

Your phone or tablet might use USB-C instead of micro-USB. Some laptops and tablets feature a USB-C port; the Nintendo Switch uses it for power too. Since USB-C hasn’t been adopted everywhere yet, you might need to buy some USB-C to USB-A adapters to ease the transition.

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  1. It is amazing how tech has developed, these days you can’t just assume everyone uses the same USB as yours so even if you can’t carry your charger head everywhere your USB cable should not be left behind. Great post Jeff, keep up with the knowledge 👍🏾

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