MDS 05-3627A01, Rev. D
LEDR Series I/O Guide
103
11.0 PROTECTED CONFIGURATION
11.1 Introduction
The LEDR radio can be supplied in a protected (also called redundant
or “1+1”) configuration (
). The protected version is designed
to perform automatic switchover to a second radio in the event of a
failure in the primary unit.
Protected operation is important for many mission-critical or revenue
producing links. By configuring two identical LEDR radios in parallel
and including a third switch box containing the RF switching circuits
and the customer interfaces, it is possible to protect against failure in any
of the LEDR radio sub-systems. Failures can be either malfunction or
external environmental effects, such as multipath fading or nearby light-
ning strikes.
A Protected station consists of two standard LEDR Series radios and a
Protected Switch Chassis (
). Ordinarily, the three chassis are
mounted together in a “stacked” arrangement, one above the other, with
one rack unit of space in between.
The top unit is referred to as the system’s “Unit A”, and the lower one
as “Unit B”. Each unit is considered to be the “sibling” of the other. The
sibling of Unit A is Unit B, and the sibling of Unit B is Unit A. This dis-
tinction is used in the
rdnt
under the sub-
heading “Read & Write Commands.”
Invisible place holder
Figure 21. Protected Switch Chassis (PSC)
