The Headset Profile (HSP) or Hands Free Profile (HFR) is a Bluetooth profile that allows headsets
to communicate with Bluetooth devices. The communication
concerns both voice input and voice output. The HSP profile is based on the Serial Port Profile (SPP) and uses this for the exchange of AT commands to control the headset. The bandwidth for mono transmission is 3.1 kHz, the sampling rate is 8 kHz. The connection establishment and the connection termination are carried out via the interconnected audio gateway.