VTI Instruments Corp.
18
EX2500A Preparation for Use
EMI Environment
Copper cable is susceptible to electromagnetic interference, which can corrupt files or generate
additional Ethernet traffic in the form of reissued messages. Fiber cable is not susceptible to these
electromagnetic sources of interference. Using fiber optic cabling with the EX2500A allows for
control of a test chassis from a computer located far away from the test lab or in areas that are near
elevators, fluorescent lighting, or other sources of high external noise.
Current LAN Implementation
If the potential location of an EX2500A is on an existing 10/100 Mb/s network, a gigabit fiber
connection will not fit without additional network equipment. At a minimum, a switch with a
gigabit fiber port is needed to connect fiber to the EX2500A. On the other hand, another Cat 5e
UTP patch cord would be the only requirement to put the EX2500A on the existing network.
F
IBER
V
S
.
C
OPPER
The table below summarizes some of the differences between fiber optic and copper cabling:
F
IBER
C
OPPER
Bandwidth
Gigabit
Gigabit
Distance
40 km+ @ 1,000 Mb/s
100 m @ 1000 Mb/s
Noise
Immune
EMI/RFI susceptible
Security
Almost impossible to tap
Susceptible to tapping
T
ABLE
2-2:
C
ABLE
C
OMPARISON
Copper Cable Recommendation
The type of copper cable VTI recommends is Cat 5e UTP (Unshielded Twisted Pair).
Fiber Optic Cable Recommendation
Fiber optic cables are specified by their core diameter and the type of fiber: multi-mode or single-
mode. When using a 1000BASE-SX fiber optic transceiver, three possible cable choices can be
made:
1)
62.5/125
μ
m MMF(multi-mode fiber)
2)
50/125
μm MMF
3)
9/125 µm SMF (single-mode fiber)
In the descriptions above, the first number refers to the diameter of the fiber optic core, and the
second number refers to the diameter of the cladding. The cladding is the outer diameter and the
core refers to the cable’s inner diameter. (See Figure 2-2 below.)
Core
Cladding
Cable Jacket
F
IGURE
2-2:
F
IBER
O
PTIC
C
ABLE
C
ROSS
-S
ECTION
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