Allied Telesis AT-FS238b/2 - Manual (Page 12)

Overview
2
Introduction
The fiber optic port on the bridging converter offers an important advantage
over fiber optic ports commonly found on Fast Ethernet equipment. It can
simultaneously transmit and receive Ethernet data for full-duplex operation
over a single fiber strand. In comparison, a conventional fiber optic port
requires two fiber strands for full-duplex operation.
In a conventional fiber optic installation, each fiber optic strand carries only
one data stream at a time and in only one direction, as illustrated in Figure 1.
Figure 1 Data Stream on a Single Fiber Strand
The data stream is transmitted at a specific wavelength, typically 850
nanometers (nm), 1310 nm, or 1550 nm. These wavelengths are known for
their low attenuation.
Full-duplex operation in a conventional fiber installation involves two
separate fiber strands, one for transmitting data and another for receiving
data, as illustrated in Figure 2. Both data streams are transmitted at the
same wavelength, but since each is on a separate strand, the signals remain
separate.
Figure 2 Full-duplex Operation on a Conventional Fiber Optic Installation
The fiber optic port on the bridging converters combines two data streams
onto one fiber optic strand. This allows you to use more of the bandwidth
inherent in fiber cable and so significantly increase the efficiency of your
existing fiber optic backbone network.
Fiber Strand
Data Stream
λ1
λ1
λ2