Verilink AS2000: The Basics (880-502981-001) Product Manual Instrukcja Użytkownika Pobierz pdf (Strona 172)

Acronyms and Definitions

Glossary-52 Verilink Access System 2000: Basics

yellow alarm A T1 alarm signal sent back toward

the source of a failed transmission

in a DS1 transmission path. Also

known as remote alarm indication

signal (RAI). Yellow alarms are

transmitted by a

Channel Service

Unit (CSU)

or DSX-1 device which

is in a red alarm condition such as

loss of signal (LOS)

loss of

frame (LOF)

, or received

alarm

indication signal (AIS)

yellow alarm transcoding When a T1 signal undergoes

framing format conversion from

Superframe (SF/D4)

Extended Superframe Format

(ESF)

, or ESF to SF, an existing

yellow alarm

is transcoded to the

new format, and the alarm can be

detected by the network or

data

terminal equipment (DTE)

equipment. An integration time is

used before transcoding occurs so

data that looks like a yellow alarm

(in the SF mode), and to allow for

detection of a yellow alarm in the

presence of errors. For SF, the

detection and clear time is 400 ± 1

millisecond. For ESF, this time is

63 to 66 milliseconds.

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