Installation guide

Planning and Designing RIO Cable System

890 USE 101 00 October 2006

Self-healing Ring

Fiber Optic

Topology

The 490NRP954 Fiber Optic Repeaters have special features built into the signal

timing that allow multiple repeaters to be interconnected in a closed-loop ring. The

advantage of a ring topology is that if a break occurs anywhere in the ring, it will

reconfigure the network so that communications can continue.

The RIO signal is sent down both legs of the ring by the drop repeater—

simultaneously to the head repeaters. A feature is built into the repeaters so that

when a signal is received on one of the Rx lines the other Rx channel is blanked—

this prevents the same signal from being transmitted twice in the ring.

RIO I/O I/O I/OPLCP/S

Tap

RIO I/O I/O I/OP/S

Head (with RIO Drop #1)

RIO Drop #5

RIO Drop #4

RIO Drop #2

RIO Drop #3

Tap

RIO I/O I/O I/OP/S

Legend

Coaxial Cable

Fiber Optic Cable

Trunk Terminator

Note: A maximum of five 490NRP954 Fiber Optic Repeaters can be used in a ring.

Note: The maximum length of fiber cable that can be used in a self-healing ring is

10 km (32,809 ft.). The number of repeaters that can be in a ring configuration is

five. This number may be reduced by the total pulse width distortion (jitter) that

occurs on one system.

This document provided by Barr-Thorp Electric Co., Inc. 800-473-9123 www.barr-thorp.com