Facility data link (fdl) – Verilink AS2000: The Basics (880-502981-001) Product Manual User Manual
Page 139
Acronyms and Definitions
Verilink Access System 2000: Basics
Glossary-19
F
FAIS
Framed Alarm Indication Signal.
Framed all-ones signal, a type of
keep-alive signal (11111111). See
.
facility data link (FDL)
The T1 facility data link is used to
transmit framing information,
error events, and loopback
controls. FDL uses 4 kbit/s of
bandwidth to transmit data. If
your installation plans to use FDL,
make sure you have selected ESF
framing format. FDL is only
available on ESF T1 circuits.
failed second (FS)
See
.
failed signal state (FSS)
A failed signal state is declared
whenever 10 SESs occur
consecutively. (The FSS will not
clear until 10 consecutive seconds
of data are processed with no SESs
present.) New standards refer to a
failed signal state as an
unavailable signal state (UASS)
.
far-end (FE)
This refers to a circuit element at
the remote end of a network
circuit.
Far-end Alarm and Control Channel
(FEAC Channel)
A DS3 C-bit subframe used to send
alarm or status information from
the far-end terminal to the near-
end terminal. The channel is also
used to initiate loopbacks at the
far-end terminal from the near-end
terminal.
far-end block error (FEBE)
A maintenance signal transmitted
in the overhead that a bit error has
been detected in the physical layer
at the far end of the link. Used to
monitor bit error performance of
the link.
FAS
See
.
FASER
See
.