I have written a program that the user can enter an AT command for a GSM PC Card. Then it displays the results. The program is in a continuous loop until the user type in Exit. However sometimes the serial port times out or just does not give a result, I put an error terminal on the output of the device, which gives the error number 811. I clear the buffer at the start of the program and 20 sec after each command is entered. It works about 80% of the time, which is not good enough, and 20 sec for each command is extremely painful! Does anyone have an example that will help allow me to see more consistent results, using Hp Vee?