USB is a Universal Serial Bus that is used to connect computer peripherals since 1996. It has largely replaced a variety of earlier interfaces, such as serial ports and parallel ports, as well as separate power chargers for portable devices and is commonly used in a wide range of applications
Older versions of USB cables are 4 wire, with a foil shield. Newer versions have more wires (for example for high speed transfer).
Several USB plugs can be encountered in the wild: A, B, C, mini, micro, and USB3 plugs. They all can provide power at 5 volts nominal.
‘USB on the go’ in short OTG is a standard created for mobile phones where the mobile phone acts as host.
Note: USB cables that are only used for charging (e.g. power banks) often don’t have the data connection wires (as that makes them cheaper). If you try to use them for a connection where data must be transferred, it can take quite a while to discover this. Sometimes the charging cables have different markings or you can label them yourself of course.