The problem when dealing with technology is that it is always changing. Planned obsolescence sometimes means change for change’s sake (such as bigger tailfins on cars in the 1950s). In our businesses, however, it often means the new technology offers new application opportunities. Let’s test your knowledge of some of these changes. Answers and explanations are in red.

1. The Telecommunications Industry Association (TIA) standards committees just approved the latest version of laser-optimized multimode fiber. What is that fiber called?
A. OM2
B. OM3
C. OM4
D. OS3

Now we have four grades of MM fiber, with OM4 offering the highest bandwidth.

2. The TIA created this new fiber to _________.
A. Be more compatible with the latest passive optical network (PON) architectures
B. Offer higher bandwidth for 10 gigabits per second Ethernet
C. Have lower loss at 1,550 nm for CATV
D. Be more compatible with long distance dense wave division multiplexing (DWDM) systems

The higher bandwidth allows multimode fiber to reach longer distances at 10 gigs per second, keeping fiber’s advantage over copper.

3. This new fiber uses a bandwidth specification that _________.
A. Is more indicative of its bandwidth with lasers
B. Is easier to test
C. Makes the fiber look better
D. Reduces cost

The new fiber uses a bandwidth test that uses modal power distribution more like a laser, the typical source used for high speed networks.

4. The TIA also recently approved Category 6a, the unshielded twisted-pair (UTP) equivalent of this fiber.
True
False

Cat 6a was also developed to allow 10 gig Ethernet to work over UTP for 100 m, albeit at very high power consumption compared to fiber.

5. Although there still is a lot of Category 5 cable being used, it is not approved for use with _________.
A. Gigabit Ethernet
B. 10 gigabit Ethernet
C. Power over Ethernet
D. All of the above

Cat 5 was designed for 100 Mb per second Ethernet and was deemed not capable of anything faster, so “enhanced Cat 5” was created.

6. In the flood of new standards, Wi-Fi also upgraded to a new version called _________.
A. IEEE 802.11b
B. IEEE 802.11g
C. IEEE 802.11n
D. WiMax

IEEE 802.11n uses six channels of connections to get higher throughput.

7. The latest version of Wi-Fi allows equaling the data-transmission capacity of _________ for compatible wireless devices.
A. 10 megabit Ethernet
B. 100 megabit Ethernet
C. 1 gigabit Ethernet
D. 10 gigabit Ethernet

Each user has a practical connection throughput of about 100 Mb per second.

8. In order to get full performance from this latest version of Wi-Fi, it is
necessary to connect it to the
network through a(n) _________ switch.
A. Gigabit Ethernet
B. 10 gigabit Ethernet
C. Power over Ethernet
D. Optical fiber

The IEEE 802.11n standard uses up to six frequencies at about 100 Mb per second, requiring a gigabit Ethernet switch to get full performance.

9. Wireless access points designed to the latest version of Wi-Fi may consume too much power to allow powering over category-rated UTP using power over Ethernet.
True
False

Current PoE standards (IEEE 803.3af) only allows 13W max, too little for many 802.11n Wi-Fi access points, especially those using more than two antennas/frequencies. Even the higher power PoE may not be enough for all “n” access points.

10. Power over Ethernet standards (IEEE 803.3af) are being upgraded to higher power (IEEE 803.3at), with total power available around _________.
A. 13 watts
B. 25 watts
C. 50 watts
D. 60 watts

The max power is limited by resistive losses in the small conductors of UTP cable over long cable runs. Some vendors offer higher power products for short cable runs but care needs to be exercised in their use.

HAYES is a VDV writer and educator and the president of The Fiber Optic Association. Find him at www.jimhayes.com.