isdninfo(4)							   Special files						       isdninfo(4)

NAME

       isdninfo - ISDN status device

SYNOPSIS

       #include <linux/isdn.h>

DESCRIPTION

       /dev/isdninfo  is a character device with major number 45 and minor number 255.	It delivers status information from the Linux ISDN subsys-
       tem to user level.

DATA FORMAT

       When reading from this device, the current status of the Linux ISDN subsystem is delivered in 6 lines of text. Each line starts with a  tag
       string followed by a colon and whitespace. After that the status values are appended separated by whitespace.

       idmap  is  the  tag of the first line. In this line for every virtual channel, the Id-string of the corresponding lowlevel driver is shown.
	      If no driver is loaded, a - (hyphen) is shown.

       chmap  is the tag of line 2. In this line for every virtual channel, the channel number of the corresponding lowlevel driver is	shown.	If
	      no driver is loaded, -1 is shown.

       drmap  is  the tag of line 3. In this line for every virtual channel, the index number of the corresponding lowlevel driver is shown. If no
	      driver is loaded, -1 is shown.

       usage  is the tag of line 4. In this line for every virtual channel, the current usage is shown. The following usage constants are defined:

	      ISDN_USAGE_NONE (0)
		     Unused channel

	      ISDN_USAGE_RAW (1)
		     Channel used by raw device (currently unsupported)

	      ISDN_USAGE_MODEM (2)
		     Channel used by some ttyI

	      ISDN_USAGE_NET (3)
		     Channel used by an ISDN net-interface

	      ISDN_USAGE_VOICE (4)
		     Channel used by some ttyI in voice mode.

	      ISDN_USAGE_EXCLUSIVE (64)
		     Channel exclusively preserved for a net-interface. This value is logically or'ed with one of the other codes.

	      ISDN_USAGE_OUTGOING (128)
		     Channel is used outgoing. This value is logically or'ed with one of the other codes. It is set, when dialling is started  and
		     reset,  when  either dialling failed or after hangup. Therefore, it is not always an indicator for an established connection.
		     To get a reliable indicator for an established connection, the driver flags (see below) have to be inspected also.

       flags  is the tag of line 5. In this line for every driver slot, it's B-Channel status is shown. If no driver is registered in a slot, a  ?
	      is  shown.   For every established B-Channel of the driver, a bit is set in the shown value. The driver's first channel is mapped to
	      bit 0, the second channel to bit 1 and so on.

       phone  is the tag of line 6. In this line for every virtual channel, the remote phone number is shown if the channel is active.	A  ???	is
	      shown, if the channel is inactive.

BLOCKING BEHAVIOUR

       After opening the device, at most 6 lines can be read by a user process.  After that, the user process is blocked. Whenever a status change
       happens, the process is allowed to read 6 more lines, starting with line one.

IOCTL FUNCTIONS

       Currently, there are two ioctl calls supported:

       IIOCGETDVR
	      Get Revision information.
	      Returns an unsigned long value v, representing various user level interface revisions, where

	      (v & 0xff)
		     is the revision of the modem-register info, available via ioctl on /dev/isdnctrl.

	      ((v >> 8) & 0xff)
		     is the revision of the net-interface config data, available via ioctl on /dev/isdnctrl.  and

	      ((v >> 16) & 0xff)
		     is the revision of the data delivered via /dev/isdninfo itself.

       IIOCGETCPS
	      Get transfer statistics.
	      Returns the number of bytes transferred so far for all virtual channels. The third parameter should be a	pointer  to  an  array	of
	      unsigned long of size ISDN_MAX_CHANNELS * 2. This array is filled with the byte counter values upon return.

OTHER CONSTANTS

       There are some more useful constants defined in /usr/include/linux/isdn.h:

       ISDN_TTY_MAJOR
	      The major device number of /dev/ttyI.

       ISDN_TTYAUX_MAJOR
	      The major device number of /dev/cui.

       ISDN_MAJOR
	      The major device number of /dev/isdnctrl, /dev/isdninfo, /dev/ippp and /dev/isdn

       ISDN_MAX_DRIVERS
	      The number of driver slots.

       ISDN_MAX_CHANNELS
	      The number of virtual channels.

       ISDN_MINOR_CTRL
	      The minor device number of /dev/isdnctrl0.

       ISDN_MINOR_CTRLMAX
	      The minor device number of /dev/isdnctrl63.

       ISDN_MINOR_PPP
	      The minor device number of /dev/ippp0.

       ISDN_MINOR_PPPMAX
	      The minor device number of /dev/ippp64.

       ISDN_MINOR_STATUS
	      The minor device number of /dev/isdninfo.

       Other constants, necessary for ioctl's on /dev/isdnctrl are listed in isdnctrl(4).

AUTHOR

       Fritz Elfert <fritz@isdn4linux.de>

SEE ALSO

       isdnctrl(4), icnctrl(4).

ISDN 4 Linux 3.13						    1999/09/06							       isdninfo(4)