^ Äëíê~ ÅíK= The reflection of sunlight by mirrors or known as the heliograph is an early method of optical wireless communication (OWC). Naturally, modern communication system reveals much higher data rates with better quality of service (QoS) compared to those ancient methods. There are many advantages of OWC which are important for a terrestrial system for example the usage of an outdoor free space optics (FSO) system. In this paper, a description and system performance characterization of the FSO such as attenuation, bit error rate (BER), Q factor and the type of detectors that are highly useful for detection in FSO systems are presented. The system are designed and simulated for performance characterization considering Subang terrestrial.