Specifications

RADring
Installation & Operation Manual Functional Description
3/11/98 12:33 RI/RO Modules Functional Description 2-25
2.8 RI/RO Modules Functional Description
General
The RI/RO modules provide connection to adjacent hubs/access units,
enabling ring expansion. There are three types of RI/RO modules:
Transparent RI/RO - (TIO module)
The TIO module is transparent to the Token Ring Signal.
Repeaters - (TFR and TCR modules)
The TFR and TCR modules provide full retiming, regeneration and jitter
attenuation of the Token Ring signal. This enables the limitation of signal
attenuation to be overcome, thus increasing the maximum ring length.
Repeaters are used to increase distances. A repeater is similar to an active
station: it regenerates the received ring signal and retransmits it down the
ring at the nominal level. However, unlike an active station, the repeater is
always inserted into the ring. A copper repeater nominally doubles the
recommended distance covered by a ring segment. In addition, it provides a
method of ensuring that large rings will continue to operate even if only one
station is active on the ring. The jitter attenuation feature in each repeater
ensures optimal performance and increased station counts.
To achieve significantly greater ranges, fiber optic cables are used. Among
other advantages, fiber optic cable provides a reliable media for the
backbone and for increased distances.
Converter - (TFC module)
The TFC module provides inexpensive signal conversion between copper
and fiber media. This also involves signal regeneration enabling extended
distance over fiber media. There are, however, limitations to using
converters instead of repeaters (see Chapter 6 for details).
All types of RADring RI/RO modules provide automatic cable break
protection and recovery. This ensures continued operation upon segment
failure, so there is no single point of failure.
TIO Ring-In/Ring-
Out Module
The TIO module functions as a Ring In or Ring Out port for connection to
adjacent hubs and access units over shielded twisted pair (STP) cables, such
as IBM Type 1 or over unshielded twisted pair (UTP) cables, such as IBM
Type 3 or screened UTP cables. The three options are provided in the same
module with a DB-9 female connector provided for STP and a shielded RJ-
45 connector provided for UTP and screened UTP. Operation of the TIO is
at data rates of 4 or 16 Mbps.