Fiber Optic InterRepeater Link
(FOIRL) An older standard of fiber optic guides used for carrying 10 MBps Ethernet. The maximum length of a segment is 1 km. A FOIRL multiport repeater and transceivers are necessary to carry the signal to multiple devices.
The more recent version of Ethernet over fiber optic cables is 10baseFL with a maximum segment length of 2 km.