Because RFL™ and Hubbell® have a policy of continuous product improvement, we reserve the right to change designs and specifications without notice.
4.5 POWER AVAILABLE FOR CHANNEL MODULES
4.5.1 MAIN SHELF
Each shelf's power supply must provide sufficient power for the Common Modules, channel modules,
and Optical Interface Adapters (OIAs) in that shelf. The power requirement for each Common Module
is 2 watts. This means a terminal multiplexer Main Shelf equipped with a 50-watt supply and an
electrical E1 interface has 48 watts available for channel modules (50 watts minus 2 watts for the
Common Module). A terminal multiplexer Main Shelf with a 50-watt supply and a fiber optic interface
has 45.4 watts available for channel modules (50 watts minus 2 watts for the Common Module and 2.6
watts for the OIA).
A drop/insert multiplexer Main Shelf has two Common Modules, one for each direction. This means a
drop/insert multiplexer Main Shelf equipped with a 50-watt supply and an electrical E1 interface has
46 watts available for channel modules (50 watts minus 4 watts for the Common Modules). A
drop/insert multiplexer Main Shelf with a 50-watt supply and a fiber optic interface has 40.8 watts
available for channel modules (50 watts minus 4 watts for the Common Modules and 5.2 watts for the
OIAs).
4.5.2 BUS REPEATER MODULE
The Bus Repeater Module (BRM) and its associated Module Adapter, the MA-500, allow multiple
physical chassis to function as one large chassis. The system is configured with a single master chassis
or Main Shelf which contains the Common Module, channel modules, etc. and one or more slave
chassis or Repeater Shelves. Power can be applied to each chassis either by a local power supply or
through a power jumper cable. A single bus repeater system is designed to work with up to five chassis
total.
The BRM is a double card module which appears to the Main Shelf bus as a channel card. The BRM
takes signals from the backplane and drives them onto a connector on the I/O Adapter. From there the
signals are daisy-chained from chassis to chassis. The Main Shelf and furthest Repeater Shelf add
termination to the signal lines to preserve signal integrity.
In the Repeater Shelf, the BRM appears essentially as a common logic card, receiving signals from the
cable, buffering them, and placing them on the backplane. The TxAddr and TxData lines are generated
by the channel cards, and thus by the Repeater Shelf, and are transferred back to the Main Shelf in a
similar way.
The SCB Data line is a bi-directional signal with no independent handshaking lines. This signal runs at
no more than half of the basic E1 rate, and has special waveshaping circuitry on the common logic. As
such, it is not manipulated by the BRM, but is simply passed from backplane to backplane.
Refer to paragraph 2.3.2 for more information on the Repeater Shelf.
IMUX 2000E1 RFL Electronics Inc.
January 1, 2008 4-6 (973) 334-3100
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