The DMS-GF/HF series (RS-232, RS-422) optical data transmission devices enable digital signals to be transmitted quickly and reliably over short distances through a serial interface. Typical applications include automated guided vehicles (AGV), rail-guided vehicles (RGV) and overhead monorail systems where a wireless link is provided between the vehicle and a fixed docking station. Through FSK modulation, IR light is rapidly switched between two different frequencies as data travels up to a 3-meter range.