Nortel 10292FA, Installation Manuallines

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64 Glossary
212257-B
single-mode fiber
See SMF.
SMF
A mode is one of the various light waves that can be transmitted in an optical
fiber. Each optical signal generates many different modes, but in single-mode
fiber the aim is to only have one of them transmitted. This is achieved through
having a core of a very small diameter (usually around 10 micrometers), with
a cladding that is usually ten times the core diameter. These fibers have a
potential bandwidth of 50 to 100 GHz per kilometer.
Tx
transmit
A device that includes a LED or laser source and signal conditioning
electronics that is used to inject a signal into optical fiber.
U
(vertical) unit
One U is 1.75 inches. Standard equipment racks have bolt holes spaced
evenly on the mounting rails to permit equipment that is sized in multiples of
this vertical unit to be mounted in the same rack.
WAN
wide area network
A physical or logical network that provides data communications to a larger
number of independent users than are usually served by a LAN and is usually
spread over a larger geographic area than that of a LAN.
wavelength
All electromagnetic radiation (radio waves, microwaves, ultraviolet light,
visible light, etc.) is transmitted in waves, and the wavelength is the distance
between the successive crests of the waves. In optical networks, you can think
of different wavelengths as being different colors of light. Wavelengths of
light are measured in nanometers or microns.