HI monks,

This time, the problem I meet is about to deal with a old snippet. This snippet receive the reqeuest from com port and answer some data. this snippet written in C works very fine until the modem is broken. Considered transmit speed and expense of buying new modem, I intend to write a perl snippet as below figure:

        _____    socket      _____  com1
        |   |________________|    |----|
        |   |                |    |----|    
        -----                ------com2
[download]

That is , I circutly connect com1 and com2 in this machine. The new snippet listen some tcp port and forward the data between tcp and com port. The benifit is that I don't modify the old program.

Let's see the code took about 5 mins to me(a big advantage of perl ;))

     use IO::Socket;


$server = IO::Socket::INET->new(Listen    => 5,
                              LocalAddr => 'localhost',
                              LocalPort => 10001,
                              Proto     => 'tcp');
open( PORT, "+>COM1" ) or die "Can't open COM1: $!";
binmode(PORT);
    while ($client = $server->accept()) {
        
        while($response = <$client>){
        
        
        print PORT $response;
        sleep 1;
        while(read(PORT, $tem_response,2048)){
            print $client $tem_response;
} 
    }
}

close($server);
[download]

Fortunatly, I can see the data from com2. Unfortuately, the program can't tell the command from com2 at all! I suspect two points:

• whether I should load Win32::serialport package and set some parameters like baud or stop bit etc.
• whether I should pack the data before transmiting?

But I think seeking the monks wisdom before I tried like a chicken with it's head cut off.;)
TIA