Manual browser: btsco(4)

BTSCO(4) Kernel Interfaces Manual BTSCO(4)


btscoBluetooth SCO Audio


btsco* at bthub?
audio* at audiobus?


The btsco driver provides support for Bluetooth SCO Audio devices through the audio(4) driver.

The btsco driver must be configured at run time with the btdevctl(8) program. The following properties are used by the btsco driver during autoconfiguration:

Local device address.
Remote device address.
The btsco driver matches the ‘HF’ and ‘HSET’ services. For the ‘HF’ service, the btsco device will, on open(2), listen for incoming connections from the remote device. Otherwise, btsco will attempt to initiate a connection to the remote device.
This integer value is not used directly, but will be stored and passed via the BTSCO_INFO ioctl as below:

SCO connections require a baseband connection between the two devices before they can be created. The btsco driver does not create this, but can provide information to facilitate an application setting up a control channel prior to use, via the BTSCO_INFO ioctl(2) call on the mixer device, which returns a btsco_info structure as follows:

#include <dev/bluetooth/btsco.h> 
struct btsco_info { 
	bdaddr_t	laddr;		/* controller bdaddr */ 
	bdaddr_t	raddr;		/* headset bdaddr */ 
	uint8_t		channel;	/* RFCOMM channel */ 
	int		vgs;		/* mixer index speaker */ 
	int		vgm;		/* mixer index mic */ 
#define BTSCO_INFO	_IOR('b', 16, struct btsco_info)

The btsco driver can be configured to act in Connect or Listen mode. In Connect mode, the btsco driver will initiate a connection to the remote device on an open(2) call, whereas in Listen mode, open(2) will block until the remote device initiates the connection.


The btsco driver was written for NetBSD 4.0 by Iain Hibbert under the sponsorship of Itronix, Inc.


btsco takes no notice of the HCI Voice Setting in the Bluetooth controller, and this must be 0x0060 (the default) as alternate values are currently unsupported.
October 4, 2006 NetBSD 7.0