Development of a medium-/small-scale local area optical fiber loop network

This report describes the outline of an optical loop network which is the most suitable for a system consisting of about 200 terminals. Upon development of an optical local-area network (LAN) to be used within this range, the compact, low cost, and general purpose properties, as well as the reliability and expandability of the system should be considered first. Especially, determination of the transmission rate and selection of the microprocessor to be used are important items to realize the compact and low cost network as desired. There are two examples for such systems which are used actually now. One is the HLN-8140 Loop, which is suitable for small-sized systems. It is a packet switching loop network using the token-passing method with a transmission rate of 1 Mbit/s. Another example is the HLN-8380 Loop which can cover up to medium-sized systems. It is a circuit-switching loop network with a transmission rate of 10 Mbit/s, and it allows transparent communications to be made via telephones and facsimiles.