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Aggregate Control
Module
Aggregate Trunk
Alarms
Base Card
B8ZS (Binary Eight
Zero Suppression)
bps
Buffer
Card
CCITT
Channel
Channel Module
Channel Interface
Module
Circuit
APPENDIX F
GLOSSARY
This module interfaces the 16.896 MHz Fast Bus with a full duplex aggregate
trunk connected to a remote node. It buffers data from the Fast Bus and reforms it
according to the transmit frame by adding overhead and frame sync bits. Piggy-
back Cards on board the Aggregate Control Module then prepare the data to comply
with transmission standards (EIA or CCITT). The receive section locates the
frame sync bits in the receive aggregate data stream, and, using these bits as a
reference, disassembles the remainder of the data stream into channel data,
channel controls, and overhead bits.
A communication line, usually full duplex, which transports data between two
nodes.
These are raised when a malfunction is detected in the system. Major alarms
need immediate attention. Minor alarms are not immediately detrimental to the
working of the system. Major alarms indicate that hardware on a Common Mod-
ule is malfunctioning. Minor alarms indicate that the malfunction is in one of
the Data or Voice Channel Modules.
A board that can have one or more cards called "piggybacks" plugged into it. It
can be tested, removed, and replaced as a unit independent from the piggyback
card(s).
Timing is critical in a digital T1 network. If too many consecutive zeros are in
the aggregate data stream, the system may lose synchronization. B8ZS is a
method used to meet the "ones density" constraints by taking strings of zeros,
converting them to ones and zeros, and placing them back into the aggregate bit
stream.
bits per second transmitted or received.
A storage device used to streamline data transfer when there is a slight difference
in data rates.
An assembly of components that can be tested, removed, and replaced as a unit. A
card usually refers to a single unit without piggybacks connected to it.
Comité Consultatif International Télégraphique et Téléphonique. A committee
that sets international communications standards.
Part of a circuit path through several entities in a communication
channel runs between two nodes.
A Voice III, VLBRV, CELP or Data Channel Module that plugs into an Expansion
Shelf. It interfaces external equipment coming in via cables to a Channel Inter-
face Module.
This module interfaces Channel Modules and the 16.896 MHz Fast Bus. It con-
tains all the circuitry necessary to control, frame, multiplex, and demultiplex up
to 64 channels onto the Fast Bus. Channel Card connections to the Channel Inter-
face Module are made via a pair of ribbon cables that run from the backplane of
the Expansion shelf, holding the channel cards, to the Main Shelf Backplane
where the Channel Interface Module is located.
An end-to-end data path which can pass through several entities in a communica-
tion system. A circuit is described or referred to by the node/channel names
which become connected by the existence of the circuit.
system.
A
F-1
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