User's Manual Part 4

RBS 2308 and RBS 2309 User’s Guide
IP Internet Protocol
IR
Infrared
IS Interface Switch
ITU International Telecommunication Union
IWD Interwork Description
IXU
Interface and Switching Unit
JTC Joint Technical Committee
kbps
Kilobits per Second
LAN Local Area Network
LAPD
Link-Access Procedures on D-Channel
LAPD is the data link layer (layer 2) protocol used for
communication between the BSC and BTS on the Abis
interface.
Abis layer 2 is sometimes used as a synonym for LAPD.
LBO Line Build-Out
LED Light-Emitting Diode
LLB Line Loopback
Lm
Half-rate traffic channel.
LNA
Low-Noise Amplifier
local bus
Offers communication between a CMRU (DXU) and
DMRUs (TRU and ECU).
local mode
An RU in local mode is not communicating with the BSC.
local/remote
switch
Switch used to set RUs to local or remote mode.
LOF Loss of Frame
logical channel
Represents a specified portion of the information-carry
ing capacity of a physical channel.
GSM defines two main categories of logical channels:
• TCH – for speech or user data traffic
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EN/LZT 720 0027 Uen R8A 2006-06-27