This is a little thing I wrote that simulates a telephone ring via the Linux console. The underlying console is used so that it can be used for Tcl and/or Tk.
I'd rather that this work via an open'ed FD on /dev/console but I can't seem to get that to work. It will ring ok, but doesn't change the frequency as it does via echo. But it does open a door to a lot of simple sound possibilities via the PC speaker, and without any extensions. Alarm clocks, fancy alerts, whatever...
This is not perfected yet. If run under a user's desktop it needs to be run by root (su root),
# ring proc by Mike Tuxford
proc ring {} {
# duration (ms)
exec /bin/echo -e '\\33\[11\;40]' > /dev/console
for {set i 0} {$i < 8} {incr i} {
# freq. (HZ)
exec /bin/echo -e '\\33\[10\;770]' > /dev/console
exec /bin/echo -e '\\a' > /dev/console
after 40
exec /bin/echo -e '\\33\[10\;870]' > /dev/console
exec /bin/echo -e '\\a' > /dev/console
if {$i == 3} {
after 200
} else {
after 40
}
}
# From the kernel console.c
# Here is the default bell parameters: 750HZ, 1/8th of a second
# reset the defaults
exec /bin/echo -e '\\33\[10\;750\]\\33\[11\;125\]' > /dev/console
return
}
ring