Alcatel-Lucent 1643 AMS Operation Manual page 380

Glossary
Tributary
A signal of a specific rate (2 Mbit/s, 34 Mbit/s, 140 Mbit/s, VC12, VC3, VC4, STM-1,
or STM-4) that may be added to or dropped from a line signal.
Tributary Overhead Controller (TOC)
SLM circuit pack that allows access to the overhead bytes of the incoming tributary
signal.
Tributary Overhead Controller (TOHCTL)
OLS circuit pack that allows access to the overhead bytes of the Supervisory channel.
Tributary Unit (TU)
An information structure that provides adaptation between the lower order path layer and
the higher path layer. Consists of a VC-n plus a tributary unit pointer TU PTR.
Tributary Unit Pointer (TU PTR)
Indicates the phase alignment of the VC with respect to the TU in which it resides. The
pointer position is fixed with respect to the TU frame.
TSA
Time Slot Assignment
TSI
Time Slot Interchange
TTP
Trail Termination Point
TUG
Tributary Unit Group
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U UAS
UnAvailable Seconds
UIM/X
A package that is used for developing the WaveStar® ITM-SC GUI for X-windows.
ULDT
Ultra Long Distance Transmission
Unacknowledged Information Transfer Service (UITS)
The unconfirmed mode of operation of the LAPD protocol.
Unavailable Seconds
A performance monitoring parameter.
Uninterruptable Power Supply (UPS)
Allows connected computer equipment to gracefully shutdown and therefore prevents
damage in the case of a power failure. Also absorbs dips in the power supply.
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GL-34 Alcatel-Lucent - Proprietary
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365-312-803R7.2
Issue 4, May 2007