The micro:bit module’s main microcontroller is called the Nordic nRF51822 system on a chip (SOC). It’s the processor that runs your MicroPython scripts, but it also has a built-in radio. In MicroPython, this radio can work with either the Bluetooth or the Nordic Gazell communication protocols.
Bluetooth makes devices like wireless earbuds, mice, and keyboards pair with devices like computers, tablets and phones. After pairing, the two devices work much like their “wired” counterparts.
Nordic’s Gazell protocol allows more than just two micro:bit modules to be part of the conversation, and it also takes fewer memory resources, making room for more statements in your scripts.
A communication protocol is a set of rules two devices can follow to exchange information.
Bluetooth is named after a 10th Century Viking king named Harald “Bluetooth” Gormsson, who brought together various Danish tribes into a kingdom. Now, computers and phones use Bluetooth to bring various other devices together with its radio communication protocol.