---
tags:
  - bluetooth
  - networks
  - radio
---

# Bluetooth frequency hopping

Bluetooth transmits on the 2.5GHz frequency band. As this is an unlicenced band
there can be interference to the signal and interception.

To get around this, bluetooth engages in **frequency hopping**. It rapidly
switches its channel of transmission between 79 distinct frequences within the
2.5GHz band where each channel occupies a bandwidth of 1MHz.

Each available band is divided into time slots. This allows multiple devices to
communicate simultaneously without interfering with each other (that much). The
[master device](./Bluetooth_piconet.md) controls the sequencing and
synchronisation of the time slots.
