High bandwidth optical wireless communication links are of prime importance, having tremendous potential to serve for the future huge data transmission requirements especially for the next generation optical networks. The inherent electromagnetic nature of the transmitted optical signals and the stochastic nature of the earth atmosphere create a number of technical challenges preventing widespread acceptance of technology and its implementation. One of the major concerns for Free Space Optics (FSO) links is fog that causes very high attenuation over non-negligible amounts of time. Another technology offering negligible fog attenuation and acceptable data rates is license free ISM band, which can be used as back up link. However, a switch-over mechanism is required for optimal selection of any link depending on weather condition and link quality maintaining an acceptable data rate. Moreover, synchronization of transceivers is the basic requirement of a communication link. This paper presents an implementation of a self-synchronizing switch-over system and the behaviour of this hybrid network is simulated for measured fog events.