Get AN992: HANDS-FREE AND HEADSET

HFP Audio Gateway (HFP-AG) is the device that is the gateway of the audio, both for input and output, typically a mobile phone. Hands-Free Unit (HF) is the device acting as the Audio Gateway's remote audio input and output mechanism. It also provides some remote control means. Typically a wireless headset or a car kit.

Devices that are typically used for handsfree communication use Bluetooth as its wireless technology. They still require a smartphone or other device to initiate a call. These devices include Bluetooth headsets, hands-free car kits (HFCK), and personal navigation devices (PND).

Hands-Free Unit (HF) is the device acting as the Audio Gateway's remote audio input and output mechanism. It also provides some remote control means. Typically a wireless headset or a car kit.

The two roles are called the Audio Gateway (AG), and Headset (HS) or Hands-Free (HF). The AG is typically a phone or computer that is connected to a remote data source. It controls the HS that acts as the remote microphone and speaker and includes commands to answer, hang up, ring, and control the volume.

Hands-Free Profile (HFP) is used to allow hands-free devices such as carkits and headphones to communicate with mobile phones over a Bluetooth link. Bluetooth HFP AG Test Suite can be used for evaluating Bluetooth HFP implementations, such as phones, for security flaws and robustness problems.

Hands free typically refers to a speakerphone mode (integrating speakers and mic for two way voice communication). If your headphones have a built-in mic, this could simply be a way to select using the mic input from that source.

The Hands-Free Profile (HFP) specification defines a set of functions such that a Mobile Phone can be used in conjunction with a Hands-Free device (e.g., installed in the car or represented by a wearable device such as a headset), with a Bluetooth Link providing a wireless means for both remote control of the Mobile ...

the "Stereo" device is the main high-quality playback device of the headset, while the "hands-free" device is a lower quality monophonic playback device.