reading COMM Port

Bairro dos Gri

I have a problem on an old thing.
I must read a machine that has a COM port to collect data. The guide book only state that i must read in ordinary protocol (send dtr and you will receive rtx). the rest of this guide book is full of how to intrepret the code of the data but not on "how to communicate"
i must read from com port since the collected data is only consist of sample# and analysed sample (coded) and the software can't print either
so the lab guy must write down by hand all the information he/she got. i think this is a high risk process.
my intention is to make relationship between sample# and patient# followed by the output data (after decoded) and the printed in the formal format.

thanks