IEEE 802.3 10Base-F

Within the framework of IEEE, an IEEE 802.8 group was commissioned with considerations and specifications on the subject of fiber optic media. The IEEE 802.8a subgroup is concerned with CSMA/ CD LANs in this context. Basically, five alternatives were discussed, namely active rings, passive star couplers and active star couplers, each with synchronous or asynchronous transmission.

Although internal voting results clearly favored active optical star couplers( IEEE 802.3 10Base- FA), there is also a standard for passive optical star couplers( IEEE 802.3 10Base-FP).

The passive star coupler differs from the active one, among other things, in that the transmission medium and star coupler are completely passive, have no radiation and no power supply. The distance between FOMAU (Fiber Optic Medium Attachment Unit) and star coupler can be up to 500 m, support of 1,024 Ethernet nodes in a network without restriction for mixed networks with non-optical LAN segments is possible.

Besides the mentioned standards 10Base-FA and 10Base-FP, there are also 10Base-FB and 10Base-FLactivities for network extension. In 10Base-FB, the "B" stands for backbone. In this system, which is designed exclusively for backbone applications, up to 15 repeaters can be cascaded. Each segment can be max. 2 km long. The signaling is synchronous in contrast to FOIRL, 10Base-5 and others and avoids bit losses in the header. 10Base-FB also offers error detection. The other variant, 10Base-FL, is an extension of the FOIRL standard to 2 km. This variant has a maximum of five repeaters for a three-tier network hierarchy and is backward compatible with FOIRL components.