Provided by: xringd_1.20-25.2_amd64 
NAME
xringd - The Linux extended modem ring server
SYNOPSIS
xringd [ options ] [ modem_device_file ]
DESCRIPTION
The xringd Linux extended Ring server will listen on a modem device for specific ring-
delay patterns (sequences). Each sequence, when fully recognised, will execute a command
you have chosen (subject to usual unix permissions). Delays are in fact delay ranges.
Sequences and commands are read from a a configuration file. xringd does not disturb your
other modem programs, not even your getty. It coexists with them. xringd probes
(asynchronously) for the actual RING signal on the serial line.
OPTIONS
-a command_on_each_ring
Run this command on every ring. Use perhaps to replace your boring phone ring.
-c config_file
Use an alternate configuration file. The default is /etc/xringd.conf
-d Run in debug mode (no daemon - logging = 100). xringd does not run as a daemon and
produces log messages on standard error.
-h | -?
See a mini usage info
-i msecs-ignored
If consecutive rings have a time (in msec) distance less than this one, they are
taken as one. For countries where a ring creates two sounds and modems that
subsequently cause two changes on the serial RI line. Use this option to make two
near RIs look as one to xringd. A value of 100-800 will most likely be the most
appropriate.
-l loglevel
Logging level. Default=1. Use 10+ for more info. When running as daemon you can use
-l 10 or 100 to get debug messages via syslog(LOG_DEBUG, ...). 0 means NO logging
at all.
-m modem_device_file
The modem device file (can also be given as the final argument).
-e Disables ECHO on modem device upon opening. This will avoid echo races reported
with some modems.
-n Performs only a syntax check of its configuration file. It implies -d. Try this
first when you write a new configuration file. xringd does not become a daemon and
produces log messages on standard error.
-t init_time
After a reset (or the first time it is run), the time (in seconds) to wait until
rings are accepted. Default: 15
CONFIGURATION FILE
The configuration file consists of lines of the following format:
R secs[-secs] [ R secs[-secs] ] ... : command
Each line is related to a sequence(pattern) that can be potentially matched. The command
at the end gets executed if the sequence was fully matched. A full match is found if the
delays between the rings are within the delay ranges given in the configuration line of a
sequence. A full match will also reset the state machine. It will start accepting new
rings as when run the first time. R means ring and it should always be the first symbol
in a sequence.
Comment lines start with a ``#'' symbol at the beginning of the line. Empty lines are
ignored.
Note that command lines options can also be included in the config file. A line should
start with the '-' of an option. See example below. Options -c and -n are ignored in the
config file. Options in the configuration file take precedence over the ones in the
command line.
EXAMPLE CONFIGURATION
# xringd configuration file -- sample
#
-a /usr/local/audio/bin/play /usr/local/lib/sounds/ring.au
-l 100
#
# 2 rings 10-16 sec apart followed by 30 secs silence
R 10-16 R 30 : /etc/ppp/ppp.start office1
# 3 rings 10-20 sec apart followed by 20 secs silence
R 10-20 R 10-20 R 20 : /etc/ppp/ppp.start office2
# 2 nearish rings then 1 ring after 20-26 secs, silence for 30 secs
R 1-5 R 20-26 R 30 : /usr/local/bin/turn-heater on
FILES
/etc/xringd.conf
The default configuration file.
/dev/modem
The default modem device used.
SIGNALS
The following signals have the specified effect when sent to the xringd process.
SIGINT, SIGTERM
Clean exit the server.
SIGUSR1
"Simulates" a RING as if it came from the modem.
SIGHUP Restart the internal machine ignoring any current state. Reread the config file.
Close and reopen the modem device. If a syntax error is found in a line all the
following lines are ignored. So when you restart, make sure you look at the log for
any reported errors. A better way is to always "parse" your config file with
"xringd -n" to check its syntax first.
NOTES
At the moment, xringd is device dependent on Linux kernel 1.3.48+ and serial devices that
support the TIOCMIWAIT, TIOCGICOUNT ioctl(2) calls. These were added by the same author to
the Linux kernel so that a process can wait on a modem DCD,RI,DSR,CTS change on a serial
port and can also read a kernel count of the interrupts on each one of these 4 lines. RI
was used for this program. (Other possibilities exist in using this ioctl for
instrumentation projects.) Note that these ioctls are only implemented for 16xx0 uarts
now (Jan96).
You have to use a proper serial cable for this to work. A cable with all pins properly
connected to your modem (especially the RI line for this program!) and serial port will
save you any trouble. Internal modems should normally work.
If you activate a program which uses the modem after ringd it should normally flush the
input buffer. In many cases you will have a few "RING" strings in your serial tty buffer
that will most likely confuse a dialup script (eg. chat).
The richness of the ring-delay pattern "language" is not great. However, you certainly
have many possibilities. Beware of overlaps though, and always have something that will
"unlock" any current sequence (eq. 4 consecutive rings that safely exit from any current
state).
If someone calls in while you are on the delay phase of your "pattern" then you are
obviously out of luck.
Only tone dialing phones allow quick dial that can meet short timing restrictions possibly
imposed by your configuration file. Make sure you use the redial button on the calling
phone if there is one - you will be able to "dial" in about a second. Pulse dialers may
introduce unexpected delays. If they are your only choice, use longer delays and wider
delay ranges.
It was reported by a user that the "rings" you hear on the calling handset do not directly
correspond to the ones actually heard on the receiving end. In the tests done with xringd
in a few countries, the number of rings remained the same on calling and called set. Just
leave each one of the rings you hear on the calling end to "settle" (do not break them
before they finish). A delay between a ring heard on the caller set and the equivalent
one on the called one was noticed but causes no problem for xringd. Feel free to send me
your comments on this.
Many getty-like programs may be configured to pick up the phone on the first ring.
Obviously, this will make xringd minimally useful. Make your getty to reply after 2-4
rings so that you have many possibilities open for xringd.
pppd (and probably some other programs) like to hold a tty in exclusive mode. Make sure
you start xringd before such programs, otherwise it won't be allowed to open the modem
device. Also, when such a program closes it may leave the line hung up. You need to
restart (kill -HUP) xringd in such a case. It does not make sense to run xringd on a line
which is permanently used for PPP/SLIP - such a line never "rings"!
Spurious interrupts (and thus pseudo-RINGs) may occur during modem switch on/off; run
xringd after your modem is switched on.
It is highly recommended - for security reasons - to make the configuration file
inaccessible (even for read) to anything but xringd. Treat it as a shadow-password-like
file. It is very easy for anyone to call your number and activate a command, if they know
a RING-delay sequence "password". So try not to disarm your home-alarm via it. You have
been warned!
AUTHOR
Angelo Haritsis (ah@doc.ic.ac.uk).
XRINGD(8)