What is spread-spectrum frequency hopping and why is it used by Bluetooth? Spread-spectrum frequency hopping is a communication technique used by Bluetooth that allows it to successfully connect with up to eight different devices without unwanted interference among them. This technique decreases the chance that multiple devices will transmit information on the same frequency level at the same time. Basically, Bluetooth switches regularly between 79 different randomly chosen frequencies within the designated range 1,600 times every second. This allows each of the connected devices to use a very particular portion of the available radio wave spectrum and significantly decreases the chance that they will interfere with each other. Additionally, should any interference occur, it will only last for that very short amount of time, making it negligible. Every Bluetooth device automatically uses spread-spectrum frequency hopping.