LANs today use a variety of protocols, which are all sets of rules that connect users of the network flow. Each ISO layer has a protocol to logically attach 'one station' layers to its 'peer' layers at the station with which it is communicating. One of the key LAN concepts is that all user-serving network workstations have access rights to the shared network medium. The rules which govern each network user sharing this medium are a major consideration in the network design and product selection. For example, the stations can all be peers communicating with each other with the access control distributed among all stations or access controlled by a master using a polling scheme.

Distributed network access may either be probabilistic or deterministic. The most popular probabilistic contention oriented access protocol is CSMA/CD. This CSMA/CD is defined as a system in which a station wishing to communicate with another station listens to see if any other station is sending at that time, thereby creating a carrier on the medium. Deterministic access may be obtained by an alternative method known as token passing, a generalization of central polling.

Opticomm maintains the IEEE 802.3 standard for LAN that deals with the physical and link layers as defined by the ISO/OSI reference model. Opticomm supports 802.3 Bus Topology, 802.5 Ring Topology, 802.4 Token passing Topology and 802.6 MAN slotted Ring Topology. Opticomm has implemented 10BaseFL, 10BaseE2, 10BaseE5, and 10BaseT 10Mb/s Ethernet Transceiver methods. Opticomm has also implemented 100Mb/s for fast Ethernet and FDDI backbone media converter transmission systems. Compliance to fast Ethernet allows the users to attach Ethernet segments together or to connect Ethernet Switching Hubs.

There are many computer interfaces with high speed LANs to provide a local interconnect system interface with switching hubs to workstations. Typical applications are among campuses for local training, hospitals for multi-sharing medical imaging protocols, factory local switching assembly distribution line and traffic railroad stations.

Example: Opticomm DS-105-TR is capable of transmitting 10BaseT and 100BaseT using the same CSMA/CD access method for graphic workstations over full duplex fiber systems.

The following are only a few needs and applications to which our LAN product line can provide easy answers and solutions:

	Traffic LAN Analysis Systems
	High Speed Signal Distribution for Local Area Networks
	Distance Learning among Graphic Workstations
	Gateway to Matrix Switching LAN Network Systems