Use the hex or oct built-in functions...

That would only help if you run hex() and oct() on the receiving end:

   $ perl -wE 'print hex "02"' | od -a
   0000000   2
   0000001
   $
[download]

What the OP probably wants is pack:

   $ perl -wE 'print pack "H*", "02"' | od -a
   0000000 stx
   0000001
[download]

But I advice him to use Net::Telnet.