A Bluetooth transmitter is a small device that, when paired with a Bluetooth receiver, can establish a small wireless network that has a range of about 30 feet, called a piconet. This network allows a person to synchronize different electronic devices without any cords when they are in range.
The Bluetooth transmitter works by using a frequency between 2.402 GHz and 2.480 GHz combined with a weak signal close to one milliwatt. When devices that are Bluetooth-capable get within range, they can connect automatically using the frequency signal given off by the transmitter. This signal allows the transmitter to communicate with up to eight different electronic devices at once.
Multiple devices are able to connect due to spread spectrum frequency hopping; the transmitter is able to randomly hop between 79 different channels at a rate of about 1,600 times per second. This limits the chance that any devices connected to the piconet are using the same frequency at the exact same time, and even if they are, it’s only for a few milliseconds.
This frequency hopping also keeps devices connected to the piconet from interrupting other electronic devices that may run on similar frequencies, such as baby monitors or garage doors.