더쿨라이프

The Hands-Free Profile (HFP) 1.5 specification   <=-  스펙문서를 받으시려면 여기를 클릭하세요.

The Hands-Free Profile (HFP) 1.6 specification   <=-  스펙문서를 받으시려면 여기를 클릭하세요.

Currently in version 1.6, this is commonly used to allow car hands-free kits to communicate with mobile phones in the car. It commonly uses Synchronous Connection Oriented link (SCO) to carry a monaural audio channel with continuously variable slope delta modulation or pulse-code modulation, and with logarithmic a-law or μ-law quantization. Version 1.6 adds optional support for wide band speech with the mSBC codec, a 16 kHz monaural configuration of the SBC codec mandated by the A2DP profile.

 (출처: https://en.wikipedia.org/wiki/List_of_Bluetooth_profiles)

The following roles are defined for this profile: 

Audio Gateway(AG) – This is the device that is the gateway of the audio, both for input and output. Typical devicesacting as Audio Gateways are cellular phones. 

Hands-Free unit (HF) – This is the device acting as the Audio Gateway’s remote audio input and output mechanism. It also providessome remote control means.  

4.33.3 Bluetooth Defined AT Capabilities

The new Bluetooth specific AT capabilities are listed below: 

AT+BVRA (Bluetooth Voice Recognition Activation) 

Syntax: AT+BVRA=<vrec> 

Description: 

Enables/disables the voice recognition function in the AG. 

Only support for execution command is mandated. Neither the read nor test commands are mandatory. 

Values: 

<vrec>: 0, 1, entered asinteger values, where 

0 = Disable Voice recognition in the AG, 1 = Enable Voice recognition in the AG 

+BVRA (Bluetooth Voice Recognition Activation)

Syntax: +BVRA: <vrect> 

Description: 

Unsolicited result code used to notify the HF when the voice recognition function in the AG is activated/deactivated autonomously from the AG. 

The unsolicited +BVRA:1 result code shall not be sent by the AG to the HF if the corresponding voice recognition activation has been initiated by the HF. Likewise, the unsolicited +BVRA:0 result code shall not be sent by the 

AG to the HF if the corresponding voice recognition deactivation has been initiated by the HF, regardless of which side initiated the voice recognition activation. 

Values: 

<vrect>: 0, entered as integer value, where 

0 = Voice recognition is disabled in the AG, 1 = Voice recognition is enabled in the AG 

4.25 Voice Recognition Activation 

The HF, via the AT+BVRA command, or the AG autonomously, may activate/deactivate the voice recognition function resident in the AG. Beyond the audio routing and voice recognition activation capabilities, the rest of the voice recognition functionality is implementation dependent. 

Whenever the AG supports a voice recognition function it shall support the AT+BVRA command as described in the procedures in this section. 

If the HF issues the AT+BVRA command, the AG shall respond with the OK result code if it supports voice recognition, then initiate an Audio Connection to the HF (if the Audio Connection does not already exist) and begin the voice input sequence. 

If the AG does not support voice recognition, the AG shall respond with the ERROR indication. 

When the voice recognition function is activated from the AG, it shall inform the HF via the +BVRA: 1 unsolicited result code and the AG shall initiate an Audio Connection to the HF (if the Audio Connection does not already exist) and begin the voice input sequence.

Once activated, depending upon the voice recognition implementation, the AG shall then keep the voice recognition function enabled: 

•  For the duration of time supported by the implementation (“momentary on” voice recognition implementation). In this case, the AG shall notify the HF by sending a +BVRA: 0 unsolicited result code. 

•  Or until the AT+BVRA command is issued to disable voice recognition from the HF. 

•  Or until the current Service Level Connection between the AG and the HF is dropped for any reason.