A local area network (LAN) is a group of computers interconnected by multiple computers and other devices in an area that are physically separated from each other to allow users to communicate with each other and share computing such as printers and storage devices. The way the resources are interconnected together. It is generally used for data and information transmission between short-distance computers. It belongs to a small-scale network such as a factory or an office set up by a department or a unit. Its low cost, wide application, convenient networking and flexible use are popular among users. Is currently the most active branch of computer network development.

The LAN covers a limited geographical range, with a typical distance of 0.1km to 25km. It is suitable for the connection of computers, terminals and various information processing equipment within a limited range of institutions, companies, campuses, military camps, factories, etc.

The LAN has a high data transmission rate and a low bit error rate. Its transmission rate is generally 1Mb/s to 1000Mb/s, and its bit error rate is generally between 10-8 and 10-11.

LANs are generally owned by a single unit and are easy to set up, maintain, and extend. The transmission medium commonly used in local area networks is a coaxial internal cable, a twisted pair, etc. to establish a dedicated internal line of the unit. The LAN focuses on the processing of shared information. The construction of the local area network includes servers, workstations, transmission media, and network devices. Currently, common types of local area networks include: Ethernet, Fiber Distributed Data Interface (FDDI), Asynchronous Transfer Mode (ATM), Token Ring, and Switching Switching.

Almost all LANs today are built on copper media (coax or twisted pair). To meet the more stringent requirements of Asynchronous Transfer Mode (ATM) communications, copper wire networks require expensive electronic components to maintain signal strength and integrity. In addition, copper wires are susceptible to electromagnetic interference and eavesdropping, and are not suitable in environments with high safety requirements.

Despite this, copper wire is still widely used for a long time because there is no low-cost alternative. Quartz fiber is almost impossible to achieve fiber-to-the-table (FTTD) because of its high connection cost. But now, the new technology makes plastic fiber have great appeal in LAN. Quite simply, the installation labor cost of plastic optical fiber is lower than that of copper wire and quartz fiber. Plastic fiber is more versatile and permanent to achieve high bandwidth, low cost solutions. For example, with PMMA plastic fiber, 100 Mbps can be achieved.

In short, plastic optical fiber has become the next generation standard LAN transmission medium.