Inc.jet Printer communication problem

Dear Sirs:
I have an inc.jet printer that speaks only in a complex series of non-printable characters. I need to pass the printer on the TCP port a series of bytes. my initial tests are failing. I'm looking for a means to test the values going to the printer to see what is actually going out on TCP. Is there a tool which I can use to see the values posted on to the network?

My attmpts are getting a buffer back, but its an error message. not the response expected. So I think my message is buggered to the port.

I need a better tool to debug the comms.

Kind Regards,

Wireshark or tcpdump

I got Wireshark and i need to learn how to find the posting to the printer. It seems that there is a lot more and what I'm looking for is like finding a needle in a haystack.