SmartSat is expected to undertake multiple projects in the area of optical and hybrid RF/optical communication links. This project will develop a modem for these links which can be utilised to demonstrate high-speed communications and gather channel measurements and other research data. The proposed activities include the development of a software implementation suitable for commercial off-the-shelf (COTS) software defined radios and a hardware/firmware implementation suited for high data rates, e.g., 1Gbps.