In order to install a cable plant that will meet industry standards and work with communications systems designed for using that type of cabling, it’s necessary to pick the right parts for the system. Each year, it seems the questions remain the same, but sometimes the correct answer changes! Can you pick the right parts? Correct answers and explanations are in red.
1. A corporate network is installing additional 802.11n Wi-Fi access points for the growing number of wireless users. What minimum category of unshielded twisted-pair (UTP) cable will be needed for connecting these access points?
A. Cat 5e
B. Cat 6
C. Cat 6a
D. Cat 7
An 802.11n wireless access point needs Gigabit Ethernet which runs just fine on Cat 5E.
2. When connecting video cameras to UTP cable using a balun instead of coaxial, choosing a higher
performance category-rated cable will allow for a longer video link.
Using a balun allows sending an analog video signal over the UTP cable. Higher rated cables have less attenuation at high frequencies so the video signal will suffer less attenuation, leading to better signal-to-noise (S/N) at the receiver.
3. A data center will connect servers and storage with 10G Ethernet. If the user prefers to use copper cable, what cable should be chosen?
A. Cat 5e
B. Cat 6
C. Cat 6a
D. Cat 7
10GbE is designed to operate on Cat 6A. It may work over shorter distances on Cat 6.
4. To support 10G Ethernet on UTP cable, the cable must be terminated with ________ connectors.
A. Properly rated modular 8-pin
C. Type F
10GbE uses a special modular 8-pin connector rated for Cat 6A. The RJ-45 name refers to the old telco connector, not the category-rated ones.
5. If the user prefers multimode fiber for the data center, what fiber(s) should be installed?
D. Either OM3 or OM4
10GbE runs on either OM3 or OM4 fiber that has higher bandwidth capability. OM4 may be used for longer links with more headroom.
6. Should the data center owner contemplate upgrading to 100G Ethernet, he would need to install ________.
A. Cat 7 UTP
B. OM3 or OM4 multimode fiber
C. OS1 or OS2 single-mode fiber
D. Either or both of the fiber choices
100GbE uses either multimode (OM3/OM4) fiber with a parallel solution (10X10-1Gb channels) or singlemode (OS1/OS2) fiber with a 10X10 wavelength division multiplexing (WDM) solution.
7. If the data center will use a multi-mode fiber solution for 100G Ethernet, it must plan on installing ________ fibers per port connection.
100Gbe over multimode as described in question 6 theoretically needs 10 fibers in each direction or 20 fibers totally. But the multifiber connectors have 12 fibers each so 24 fibers will be needed.
8. Most fiber optic transceivers that operate at speeds of 1–10 Gbps use ________ connectors, which also will influence the selection of patchcords for the network connections
to the cabling.
Transceiver manufacturers use LC connectors for their smaller size. If the cable plant uses ST or SC connectors, hybrid patchcords will be required.
9. In spite of all the talk about using OM3 or OM4 50/125 fiber optic cable for new installations, the old standby 62.5/125 fiber remains the most popular fiber.
Many earlier systems using 62.5/125 fiber continue to use it for expansion. It’s still used for slower data systems and other applications like video surveillance too.
10. A customer has asked if you can install the cable for a new passive optical LAN based on FTTH technology. What kind of cable plant will you need to install?
A. OM3 multimode with SC connectors
B. OM4 multimode with LC connectors
C. Single-mode with ribbon cable
D. Single-mode with one fiber to the desktop
POLs use singlemode fiber with only one fiber to the user. Most systems will probably use prefabricated systems to simplify installation.
HAYES is a VDV writer and educator and the president of The Fiber Optic Association. Find him at www.JimHayes.com.