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Glossary
Issue 1
December 1997
GL-9
Free Running
An operating condition of a clock in which its local oscillator is not locked to an internal
synchronization reference and is using no storage techniques to sustain its accuracy.
FT-2000
Lucent's SONET OC-48 lightwave system.
Function Unit
Refers to any one of a number of different circuit packs that can reside in the A, B, or C
function unit slots on the DDM-2000 OC-3 Multiplexer, or in the A, B, C, or D function unit
slots of the DDM-2000 OC-12 Multiplexer.
G
GCNS-2000
Lucent's Gigabit Cell Network Switch.
GNE
Gateway Network Element — A network element that has an active X.25 link. Can also be
a DSNE.
GR
Bellcore General Requirement
Group
The eight slots that may be equipped.
GTP
General Telemetry Processor
GUI
Graphical User Interface
H
Hairpin Routing
A cross-connection between Function Units. For example, Function Unit C to Function
Units A or B. Cross-connections go through Main, but no bandwidth or time slots are
taken from the backbone ring. Eliminates need for another shelf.
HECI
Humans Equipment Catalog Item
Holdover
An operating condition of a network element in which its local oscillator is not locked to
any synchronization reference but is using storage techniques to maintain its accuracy
with respect to the last known frequency comparison with a synchronization reference.