DBRI(4)

NAME

dbri - Dual Basic Rate ISDN Interface and audio interface

CONFIG
device-driver dbri

AVAILABILITY

SPARCstation 10 systems only.

The SpeakerBox audio peripheral is available for most dbri equipped systems and provides an integral monaural speaker as well as stereo line out, stereo line in, stereo headphone, and monaural microphone connections. The headset output level is adequate to power most headphones, but may be too low for some external speakers. Powered speakers or an external amplifier may be used with both the headphone and line out ports.

The Sun Microphone is recommended for normal desktop audio recording. When the Sun Microphone is used in conjunction with the SpeakerBox, the microphone battery is bypassed. Other audio sources may be recorded by connecting their line output to the SpeakerBox line input (audio sources may also be connected from their headphone output if the volume is adjusted properly).

DESCRIPTION
The dbri device uses the Dual Basic Rate ISDN Interface (DBRI) and Multimedia Codec chips to implement the audio device interface. This interface is described fully in the audio(4) manual page.

The AUDIO_GETDEV ioctl(2V) returns AUDIO_DEV_SPEAKERBOX to identify the dbri device type. The AUDIO_SETINFO ioctl controls device configuration parameters.

  Audio Data Formats
The dbri device supports the audio formats listed in the following table. When the device is open for simultaneous play and record, the input and output data formats must match.

    	Supported Audio Data Formats

        Sample Rate	Encoding	Precision	Channels

        8000 Hz	u-law	8	1
        8000 Hz	A-law	8	1
        8000 Hz	linear	16	1 or 2
        9600 Hz	linear	16	1 or 2
        11025 Hz	linear	16	1 or 2
        16000 Hz	linear	16	1 or 2
        18900 Hz	linear	16	1 or 2
        22050 Hz	linear	16	1 or 2
        32000 Hz	linear	16	1 or 2
        37800 Hz	linear	16	1 or 2
        44100 Hz	linear	16	1 or 2
        48000 Hz	linear	16	1 or 2

  Audio Ports
The record.avail_ports and play.avail_ports fields of the audio_info structure report the available input and output ports. The dbri device supports two input ports, selected by setting the record.port field to either AUDIO_MICROPHONE or AUDIO_LINE_IN. The play.port field may be set to any combination of AUDIO_SPEAKER, AUDIO_HEADPHONE, and AUDIO_LINE_OUT by OR'ing the desired port names together. Note that some ports may be unavailable for particular SPARCsystems.

  Sample Granularity
Since the dbri device manipulates buffers of audio data, at any given time the reported input and output sample counts will vary from the actual sample count by no more than the size of the buffers it is transferring. Programs should, in general, not rely on absolute accuracy of the play.samples and record.samples fields of the audio_info structure.

ERRORS
In addition to the errors described in audio(4), an open() will fail if:

ENODEV
    The driver is unable to communicate with the SpeakerBox, possibly because it is currently not plugged in.

FILES
/dev/audio
/dev/audioctl
/usr/demo/SOUND

SEE ALSO
ioctl(2V), audio(4), streamio(4)