A 600 GHz data transmission using the combination of a photonic emission using a uni-travelling carrier photodiode and an electronic detection is investigated. A high-definition television transmission at this carrier frequency with a very low power at the receiver is reported. Only 10 nW of terahertz (THz) power at 600 GHz was sufficient to ensure a successful high-definition video transmission. This combination of photonics at emission and heterodyne detection lead to achieving THz wireless links with a safe level of electromagnetic exposure.