Abstract: A fiber optic telecommunication system has master site linked to a plurality of subscriber interface sites by a single pair of optical fibers. Downlink messages are transmitted in a continuous TDM format over a first optical fiber from the master site to subscriber interface sites, and in a burst mode TDMA format over a second optical fiber from the subscriber interface sites to the master site. Each subscriber interface site is coupled to the optical fiber link by way of a multiple fan-out fiber coupling pedestal at a common location on the fiber pair. To prevent collisions between successive uplink bursts from the subscriber interface sites, a guard band separates successive uplink messages from one another. The guard band duration accommodates optical fiber transmission distance between the common location on the uplink optical fiber and the subscriber interface site whose differential optical fiber transmission distance from the common location is greatest.

Abstract: A data communications transceiver or configuration prevents undesired coupling between data stations by eliminating any connection between the ground path circuits of those data stations and line conductors connecting such stations together. The line conductors can be metallic and are coupled to the data stations by optical couplers. The optical couplers are powered from power sources that are totally separate and independent from any power sources associated with the data stations.

Abstract: A data link is disclosed which utilizes differential communication between pairs of transmitting and receiving devices. In particular, one device of each pair is reserved for communicating a logic"O" and the other is reserved for communicating a logic "1". The pairs are grouped to form an array which is capable of providing simultaneous parallel communication, at relatively low bit rates, between two equipment components. The communication may be either unidirectional or bidirectional between the components. The ability to integrate the arrays of transmitting and/or receiving electronics and optics allows for improved reliability of the inventive system over a single fiber, high data rate, alternative.