.\" $Id: isdninfo.man.in,v 1.4 1999/09/06 08:03:23 fritz Exp $
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.\" groff -man -Tascii isdninfo.4 for ASCII output, or
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.TH isdninfo 4 "@MANDATE@" "ISDN 4 Linux @I4LVERSION@" "Special files"
.SH NAME
isdninfo \- ISDN status device
.SH SYNOPSIS
.B #include <linux/isdn.h>
.SH DESCRIPTION
.I /dev/isdninfo
is a character device with major number
.B 45
and minor number
.BR 255 .
It delivers status information from the Linux
.SM ISDN
subsystem to user level.
.SH DATA FORMAT
When reading from this device, the current status of the Linux
.SM ISDN
subsystem is delivered in
.B 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.
.TP
.B 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.
.TP
.B 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.
.TP
.B 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.
.TP
.B 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:
.RS
.TP
.BR ISDN_USAGE_NONE " (0)"
Unused channel
.TP
.BR ISDN_USAGE_RAW " (1)"
Channel used by raw device (currently unsupported)
.TP
.BR ISDN_USAGE_MODEM " (2)"
Channel used by some ttyI
.TP
.BR ISDN_USAGE_NET " (3)"
Channel used by an ISDN net-interface
.TP
.BR ISDN_USAGE_VOICE " (4)"
Channel used by some ttyI in voice mode.
.TP
.BR ISDN_USAGE_EXCLUSIVE " (64)"
Channel exclusively preserved for a net-interface. This value is
logically or'ed with one of the other codes.
.TP
.BR 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
.B 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.
.RE
.TP
.B 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. 
.TP
.B 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.

.SH 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.

.SH IOCTL FUNCTIONS
Currently, there are two ioctl calls supported:
.TP
.B IIOCGETDVR
Get Revision information.
.RS
Returns an unsigned long value
.IR v ,
representing various user level interface revisions, where
.TP
.BI ( v " & 0xff)"
is the revision of the modem-register info, available via ioctl on
.IR /dev/isdnctrl .
.TP
.BI (( v " >> 8) & 0xff)"
is the revision of the net-interface config data, available via ioctl on
.IR /dev/isdnctrl .
and
.TP
.BI (( v " >> 16) & 0xff)"
is the revision of the data delivered via
.I /dev/isdninfo
itself.
.RE
.TP
.B IIOCGETCPS
Get transfer statistics.
.RS
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.
.RE
.SH OTHER CONSTANTS
There are some more useful constants defined in
.IR /usr/include/linux/isdn.h :
.TP
.B ISDN_TTY_MAJOR
The major device number of
.IR /dev/ttyI .
.TP
.B ISDN_TTYAUX_MAJOR
The major device number of
.IR /dev/cui .
.TP
.B ISDN_MAJOR
The major device number of
.IR /dev/isdnctrl ", " /dev/isdninfo ", " /dev/ippp " and " /dev/isdn
.TP
.B ISDN_MAX_DRIVERS
The number of driver slots.
.TP
.B ISDN_MAX_CHANNELS
The number of virtual channels.
.TP
.B ISDN_MINOR_CTRL
The minor device number of
.IR /dev/isdnctrl0 .
.TP
.B ISDN_MINOR_CTRLMAX
The minor device number of
.IR /dev/isdnctrl63 .
.TP
.B ISDN_MINOR_PPP
The minor device number of
.IR /dev/ippp0 .
.TP
.B ISDN_MINOR_PPPMAX
The minor device number of
.IR /dev/ippp64 .
.TP
.B ISDN_MINOR_STATUS
The minor device number of
.IR /dev/isdninfo .
.LP
Other constants, necessary for ioctl's on
.I /dev/isdnctrl
are listed in
.BR isdnctrl (4).
.SH AUTHOR
Fritz Elfert <fritz@isdn4linux.de>
.SH SEE ALSO
.BR isdnctrl "(4), " icnctrl (4).
