As for the purchase of Bluetooth headsets, because of the many brands of mobile phones and headsets, the most troublesome for consumers is the compatibility between mobile phones and Bluetooth headsets. The manufacturer pointed out that the Bluetooth headset has three specifications, HeadsetPro-file (HSP), HandfreeProfile (HFP) and A2DP. The HSP provides the basic functions required for communication between the mobile phone (mobile phone) and the headset. HandfreeProfile (HFP) adds some extensions to HeadsetPro-file (HSP), which was originally only used to control mobile phones from a Bluetooth headset fixed car handsfree. A2DP (Advanced Audio Transmission Specification) – Allows transmission of stereo audio signals. (The quality is much better than the mono encryption for HSP and HFP). Determine the compatibility of the headset with the phone.