com port 1 programming

Question

Hi all,

I have a device which is connected to my system com port1 and when i swipe bar code card like our office access card its having a number and that swiping machine will pass that number, then i need to catch that number and then i need to write some code to accept/deny that card.

could any one give me some suggestions to read that number and how to contact with com port1 in dot net..

thank you...