You can write direct to the /dev/dsp to make a variety of beep-like sounds of various frequencies. I take manual control over the Tk loop, to keep the eventloop from blocking while generating tones. You could make different sounds for different signals.

#!/usr/bin/perl
use warnings;
use strict;
use Tk qw/MainLoop tkinit DoOneEvent exit DONT_WAIT ALL_EVENTS/;
use Audio::DSP;

$| = 1;

my $sample_rate = 8000;
my $channels = 1;
my $format = AFMT_S16_LE;
my $buffer = 1;

my $dsp = new Audio::DSP(buffer   => $buffer,
                      channels => $channels,
                      format   => $format,
                      rate     => $sample_rate);
$dsp->init() || die $dsp->errstr();

############################################################
my $freq_adj = .1;
my $vol = .5;
my @speeds = (8000,11025,22050,44100);

##############################################################
my $mw = tkinit;
my $stop = 0;

my $adjust = 10000;
$mw->Scale(-from => 0, -to => 10000, 
                -variable => \$adjust,
         -orient => 'horizontal',
             -showvalue => 1,     
                 -command => sub {
             $freq_adj = $adjust/10000 + .01 ;
             $mw->DoOneEvent( DONT_WAIT | ALL_EVENTS );
        })->pack;

my $volume = 50; 
$mw->Scale(-from => 0, -to => 100, 
                -variable => \$volume,
         -orient => 'horizontal',
             -showvalue => 1,     
                 -command => sub {
             $vol = $volume/100 + .01 ;
             $mw->DoOneEvent( DONT_WAIT | ALL_EVENTS );
        })->pack;


$mw->Button(
    -text    => 'Start',
    -command => sub { $stop = 0; &generate  },
)->pack();

$mw->Button(
    -text    => 'Stop',
    -command => sub { $stop = 1; },
)->pack();

$mw->Button(
    -text    => 'Speed',
    -command => sub { 
                push @speeds, shift @speeds;
                $dsp->speed($speeds[0]); 
        }
)->pack();

$mw->Button(
    -text    => 'Quit',
    -command => sub {$stop = 0;$dsp->close; exit(0) },
)->pack();

#MainLoop;
$mw->DoOneEvent( MainLoop );
#################################################

sub generate{
 while(1){
 make_tone($freq_adj, $vol);
 if($stop){return};
}
}

sub make_tone {
     my $rad = 0;
     my ($freq_adj, $vol) = @_;
     while ( $rad < 6.283 ){
         if($stop){last}
         $rad +=  $freq_adj;     
     my $raw = ($vol*32768) * sin($rad);    #max times
       my $num = pack( 'V', $raw  ); 
           $dsp->dwrite($num);
        $mw->DoOneEvent( DONT_WAIT | ALL_EVENTS );
    }
}
[download]