Traditionally, serial communications
lines have been employed to transmit traffic control signals.
However, live video, as part of an intelligent transportation
system (ITS), requires a transmission bandwidth up to
100 times greater than the standard serial links. Furthermore,
the video signal often must be transmitted over a distance
of several miles, usually to a central traffic operations
center (TOC). Fiber optic cabling is the preferred medium
to carry the video signal, since fiber optic cabling has
a very large bandwidth and is immune to magnetic interference.
The combination of high bandwidth demand along with fiber
cabling has resulted in the emergence of Ethernet as the
protocol of choice for traffic control,
video surveillance
systems, and other
outdoor applications. Ethernet’s virtually unlimited bandwidth, ruggedness,
scalability, and inexpensive systems components make it
a natural for the new generation of Intelligent Transportation
Systems (ITS). |
