Bluetooth (or "Bluetooth Classic") has been used for decades on mobile phones for headsets and is good at streams of data at high data rates - ideal for audio and waveforms such as ECG and breathing waveforms. The problem with Bluetooth is that the latest standard has focused on BLE which is causing manufacturers of wearables to drop the old connection modes. The Pilot-MUX used a radio that could decode seven full Bluetooth streams simultaneously, but the chipset has now gone out of production forcing a change to BLE.