Listing 3—This Perl script translates the user camera selection commands to control the video-switching module.

#!c:/perl/bin/perl.exe
require ('.\cgi-lib.pl');
use CGI qw(:standard);
# Open the com port to write. 
system("MODE com2 baud=2400 parity=n data=8 stop=1 > try.txt"); 
open(PORT_2, "<gtcom2");
# HTML send back when requested
print "Content-type:text/html\n\n";
print <<ltEND_OF_MESSAGE;
<lthtml> <ltFORM METHOD=POST ACTION="http://server_ip_address/cgi/main.pl">
# Read previously defined button names (2 cameras)
open(GET_NAMES, "names.txt");
@names_aray = <ltGET_NAMES>
close(GET_NAMES);
for ($i=0; $i<=1; $i++) $tim[$i] = $names_aray[$i];
print "<ltCENTER> <ltinput TYPE=submit NAME='Camera1' VALUE=$tim[0]>
<ltinput TYPE=submit NAME='Camera2' VALUE=$tim[1]> </CENTER>\n\n";
# Monitor which button is pressed and write to the com port 
my $camera1 = param("Camera1");
my $camera2 = param("Camera2");
my $reset = param("Reset_Cameras");
if ($reset) {
print "<lth3 ALIGN=CENTER> Cameras reset</h3>";
for ($i=0; $i<=50; $i++) print PORT_2 "\000"; 
}
elsif ($camera1) { 
print "<lth3 ALIGN=CENTER> View $camera1</h3>";
for ($i=0; $i<=5; $i++) print PORT_2 "\000";
print "<ltscript>";
print "window.open('http://server_ip_address/ijava.htm');";
print "</script>";
}
elsif ($camera2) {
Etc ………….
}
my $temp = SHUTDOWN;
print <<ltSHUT_DOWN; <lth3> Click to shut down
<ltinput TYPE=submit NAME='Reset_Cameras' VALUE='ShutDown'> </h3> SHUT_DOWN
print <<ltEDIT_BACK; <lth3> 
<lta href="http://server_ip_address/cgi/edit.pl"<gtEdit</a></h3>
EDIT_BACK
print "</FORM> </html>";