GL-14
Issue 5 June 2000
363-206-208
Glossary
OC, OC-n
Optical Carrier — The optical signal that results from an optical conversion of an (elec-
trical) STS signal; that is, OC-1 from STS-1 and OC-n from STS-n.
OC-1
Optical Carrier Level 1 Signal (51.84 Mb/s)
OC-3
Optical Carrier Level 3 Signal (155 Mb/s)
OC-3c (STS-3c)
Optical Carrier Level 3 concatenated Signal — Low-speed broadband signal equivalent
to three STS-1s linked together with a single path overhead.
OC-12
Optical Carrier Level 12 Signal (622 Mb/s)
OHCTL
The overhead controller circuit pack provides user access to the SONET overhead
channels. Currently, this circuit pack is inserted into the AUXCTL slot.
OLIU
Optical Line Interface Unit. This circuit pack contains, among other things, the optical
transmitter and receiver.
OOF
Out of Frame.
Operations Interface
Any interface that provides information on the system performance or control. These
include the equipment LEDs, user panel, CIT, office alarms, and all telemetry interfaces.
Optical LBO
An optical attenuator that is inserted into a fiber optic line to decrease the optical power.
OOL
Out of Lock.
OS
Operations System — A central computer-based system used to provide operations,
administration, and maintenance functions.
OSI
Open Systems Interconnection — Referring to the OSI reference model, a logical struc-
ture for network operations standardized by the international standards organization
(ISO).
OSP
Outside Plan.
Summary of Contents for DDM-2000 OC-12
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