Hi .. try creating a new HypeTerminal session with the below parameters and test it again .. if still does not work then try using a different PC .. It sounds like HyperTerminal might not be configured correctly ..
"Step 2 Before connecting a computer or terminal to the ports, check to determine the baud rate of the serial port. The baud rate must match the default baud rate (9600 baud) of the Console port of the adaptive security appliance. Set up the terminal as follows: 9600 baud (default), 8 data bits, no parity, 1 stop bits, and Flow Control (FC) = Hardware. "