Abstract Reliability of communications on Industrial Plants, operating in a CIM (Computer Integrated Manufacturing) environment is considered as the nervous system of the whole plant operation. Every operation on plant level, is directly or indirectly related to the efficient communication of devices on modern manufacturing plants. In other words, the throughput of products manufactured in a CIM setting is highly dependent on the reliability of communications. Metallic medium such as coax and twisted pair cables provide fairly good service for low data transmission rates. Even though coax cables, can handle high data rates but in actual practice, it is held lower so as to maintain the integrity of data. This is due to different types of electrical noise, like EMI (Electro Magnetic Interference) and RFI (Radio Frequency Interference). They have a tendency of creeping into the metallic cable, thereby violating the integrity of transmitted data, which further aggravates at high frequencies. This problem can be alleviated by using optical fiber as the transmission medium [1,2]. This paper is oriented towards the communication problems of small industries with data rate requirement of 2 to 5 Mbps; and are trying to enter the arena of automation, evading large initial investments. The system design can be implemented on MAP (Manufacturing Automation Protocol) or PROWAY networks [5]. The optical system is comprised of an LED (light emitting diode), a multimode fiber with 50 micrometer core diameter and a PIN (P-type, Intrinsic, N-type) photodiode receiver. The analysis is supported by computer simulation results and plots between some important parameters have been demonstrated. The system is implemented on carrierband signalling, however it can be integrated with broadband facility to handle variety of data ranging from video, text, voice and graphics etc. This can be performed by appropriate protocol conversion techniques using bridges and gateways at nodal intersections.