User's Manual

SPEEDLAN 9000 Series Installation and Operation User Guide
Glossary-10
Latitude
This is the geographic latitude of the location of the terminal.
LED
This is a light-emitting diode, which is a semiconductor, that sends out visible light when an electrical current moves
through it.
Left arrow
This is the left arrow key on your keyboard.
Light Emitting Diode (LED)
An electronic device that emits light with little generation of heat.
Line Interface Unit (LIU)
The first unit inside the modem units encountered by signals from the user.
Line of Sight (radio) (LOS)
A condition whereby the antennas of a given link have a sufficient path for communication. It requires that at least 60% of
the Fresnel zone between them be unobstructed. (Do not confuse with Loss of Signal.)
Liquid Crystal Display (LCD)
The display on the Modem Unit used to configure and monitor the system.
Local Area Network (LAN)
A short distance data communications network used to link together computers and peripheral devices (such as printers)
under some form of standard control.
Loopback
This is the process of sending out a test signal to the device on the network so that you know if your signal was successful
or unsuccessful.
Loss of Signal (LOS)
The signal from the user’s device does not appear in the DSX or E1 interface. (This is not to be confused with Line of
Sight.)