Yeah that sounds exactly like it :P one of the employees explained it to me, but due to my lack of expertise in programming I didn't fully understand it.

Thanks also for your link. I tried it, but that program crashes for me (when running that piece of code the program freezes). Now, I came across another piece of code which seems to connect just fine (no error) but which does not properly send or receive any messages. Good thing to know is that when the boards receive a message they reply to it, even when the message sent is completely random. So it's likely that the sending part isn't properly functioning... Here is the code to set up the port:

my $PORT = "/dev/ttyS0";
system ("baud=19200 stop=1 data=8 parity=n");
open DEV,"+<$PORT" or die "Failed to open port\n";
my $ofh = select(DEV); $| = 0; $/='>'; select($ofh);

[download]
And here to send one of the 4 byte package and receive the output (and since there is no output, the program freezes there). This message is directed at the first board (that's why @data1 = 1). 
my @data = (3, 1, 255, 253);                
my $packeddata = pack("C*", @data);

print DEV $packeddata;

my $output = <DEV>;
#print "Output: $output ";

[download]
Thanks for all the replies so far! Let's hope we can solve this!

In reply to Re^2: Open serial port without Device::SerialPort by ThomasBrouwer
in thread Open serial port without Device::SerialPort by ThomasBrouwer

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