Specifications

Page 34 DocSTAR Level 2 Service Training Workbook
Fiber-optic Cable
Fiber-optic cable uses light pulses rather than electrical signals to communicate data.
Fiber-optic cable is made up of a very thin cylinder of glass, called the core, surrounded
by a concentric layer of glass, called the cladding. The fibers are sometimes made of
plastic, but plastic cannot carry signals as far as glass. Fiber-optic cable is uni-directional
so a pair of cables is necessary, one to send and one to receive. Fiber-optic cable is very
expensive and requires a high level of expertise to install. Some advantages to Fiber-
optic cable are:
? It can transmit data at demonstrated speeds of >1Gbps
? It can carry a signal for miles
? It is not subject to electrical interference
? It is more secure than copper wire since there are no electrical signals to be
tapped into and stolen (as is the case with conventional wiring).
Figure 3.7 Fiber-optic cable design & Fiber-optic connector
Baseband and Broadband Transmission
There are two methods for transmitting signals over network cable: Baseband and
Broadband Transmission.
Baseband Transmission uses bi-directional digital signaling over a single frequency.
Baseband transmission uses the entire available bandwidth to transmit over a single
frequency. Broadband Transmission uses uni-directional analog signaling over a range
of frequencies. Broadband transmission uses selected frequencies to transmit data and
therefore can be tuned to have multiple analog transmission systems on the same cable
such as cable television and network transmissions.