A hand-held, battery powered, wireless control station transmits alphanumeric characters and control functions to a receiver interfaced with a host computer. The control station includes a microcomputer which converts keyboard signals into a secured character code and transmits the secured character code to a computer interface transceiver using a frequency shift key modulation technique. The keyboard is a multiple function keyboard having plural shift keys allowing several character codes for each key. The computer interface transceiver only recognizes or accepts secured character codes. For the character codes accepted the computer interface transceiver forwards the character to the host computer via an RS 232 interface link. The computer interface transceiver also transmits the secured character code back to the hand-held control station which then displays the characters on a display confirming for the operator receipt of the character by the computer end transceiver. In addition, messages which originate in the computer can be transmitted to the hand-held control station and displayed on the display therein in a secure manner.