I am trying to design a user interface that will allow serial communication through a computer's serial port and to an RF modem. Actually, there will be one base modem and several other remotely located modems at a distance. I have found a couple of good examples using API calls and I am currently able to open the COM port through my GUI using these examples as guides. My next step is to try to communicate with the base modem by transmitting a packet of data (in hex) to configure one of the base modem's properties. The modem is designed to respond by sending a particular packet of data (in hex) back to the initiating end. What would be my first step in implementing this? How do I represent hex data in my code? Any help would really be appreciated.