Glossary
ST2400A SDH Test Set User Manual
G-5
Defect
A limited interruption in the ability of an item to perform a required function.
Persistence of a defect can cause a failure.
Digital Cross-connect (DCS)
An electronic cross-connect which has access to lower-rate channels in higher-
rate multiplexed signals and can electronically rearrange (cross-connect) those
channels.
Digital Signal
An electrical or optical signal that varies in discrete steps. Electrical signals are
coded as voltages, optical signals are coded as pulses of light.
E1, E2, E3, E4
Alternative names for the ITU-T 2 Mb/s, 8 Mb/s, 32 Mb/s, and 140 Mb/s
tributary signals.
ES
Errored Second; measure of network or equipment performance
ETSI (European Telecommunications Standards Institute)
Organization responsible for defining and maintaining European standards,
including SDH.
Failure
A termination of the ability of an item to perform a required function. A failure is
caused by the persistence of a defect.
FEBE (Far End Block Error)
See Remote Error Indication (REI).
FERF (Far End Receive Failure)
See Remote Defect Indication (RDI).
FIFO
First-In First-Out; a type of data buffer
Fixed Stuff
A bit or byte whose function is reserved. Fixed stuff locations, sometimes called
reserved locations, do not carry overhead or payload.
Floating mode
A virtual tributary mode that allows the VC synchronous payload envelope to
begin anywhere in the VC. Pointers identify the starting location of the VC. VCs
in different multiframes may begin at different locations.
Framing
Method of distinguishing digital channels that have been multiplexed together.
Frequency
The number of cycles of periodic activity that occur in a discrete amount of time.
Summary of Contents for ST2400A
Page 7: ...ST2400A SDH Test Set User Manual vii Index I 1...
Page 12: ...General Safety Summary xii ST2400A SDH Test Set User Manual...
Page 13: ...Getting Started...
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Page 24: ...Operating Basics...
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Page 44: ...Reference...
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Page 94: ...Reference ST2400A SDH Test Set User Manual 3 49...
Page 95: ...Appendices...
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Page 113: ...Specifications SDH ST2400A SDH Test Set User Manual A 17...
Page 134: ...Factory Defaults C 4 ST2400A SDH Test Set User Manual...