Handbook for Sound Engineers

414 Chapter 14

media distance-bandwidth product of Cat 5e and Cat 6a
with 802.11 (a, b, g, n) wireless media, often called
Wi-Fi.

New cable designs can affect size and pathway load
so consult the manufacturer. Note that cable density is
continually changing with newer, smaller cable designs.
Numbers in Table 14-18 should be considered worst
case. Designers and installers of larger systems should
get specific dimensional information from the
manufacturer.

Fig. 14-7 shows various problems that can be found

in UTP cabling.^ Fig. 14-8 gives the maximum distances

for UTP cabling as specified by ANSI/TIA.

Four (4) pair 100:±15% UTP Cat 5e cabling is the

recommended minimum requirement for residential and

light commercial installations because it provides excel-

lent flexibility. Pair counts are four pair for desktop and

twenty five pair for backbone cabling. The maximum

length of cable is 295 ft (90 m) with another 33 ft

(10 m) for patch cords.

Unshielded twisted pairs (UTP) and shielded twisted

pairs (STP) are used for structured cabling. Unshielded

twisted pairs (UTP) are the most common today. These

cables look like the POTS cable, however, their

construction makes them usable in noisy areas and at

high frequencies because of the short, even twisting of

the two wires in each pair. The twist must be even and

tight so complete noise cancellation occurs along the

entire length of the cable. To best keep the twist tight

and even, better cable has the two wires bonded

together so they will not separate when bent or flexed.

Patch cable is flexible so twist and impedance are not as

well controlled. The color codes for the pairs are given

in Table 14-19.

Cable diameter varies for the different types of cable.

TIA recommends that two Cat 6 cables but only one

Cat 6a cable can be put in a ¾ inch (21 mm) conduit at

40% fill. The diameter and the stiffness of the cables

determine their bend radius and therefore the bend

radius of conduits and trays, Table 14-20

Fig. 14-9 shows the construction of UTP and

screened UTP cable.

14.9.3.6.5 Critical Parameters

Critical parameters for UTP cable are: NEXT,

PS-NEXT, FEXT, ELFEXT, PS-ELFEXT, RL, ANEXT.

NEXT. NEXT, or near-end crosstalk, is the unwanted

signal coupling from the near end of one sending pair to

a receiving pair.

Table 14-17. Network Data Rates, Supporting Cable
Types, and Distance

Minimum

Performance

Token

Ring

Ethernet Maximum

Distance

Cat 3 4 Mb/s 10 Mbps 100 m /328 ft

Cat 4 16 Mb/s – 100 m /328 ft

Cat 5 – 100 Mbps 100 m /328 ft

Cat 5e 1000 Mbps 100 m /328 ft

Cat 6 – 10 Gbps 55 m /180 ft

Cat 6a 10 Gbps 100 m /328 ft

Table 14-18. Characteristics of Cat 5e, Cat 6, and
Cat 6a

Cabling Type Cat 5e Cat 6 Cat 6a

Relative Price (%) 100 135–150 165–180

Available Bandwidth 100 MHz 250 MHz 500 MHz

Data rate Capability 1.2 Gbps 2.4 Gbps 10 Gbps

Noise Reduction 1.0 0.5 0.3

Broadband Video Channels

6 MHz/channel

17 42 83

Broadband Video Channels

rebroadcast existing channels

6 28 60+

No. of Cables in Pathway

24 inches × 4 inches

1400 1000 700

Figure 14-6. Comparison of media distance to bandwidth

100,000

10,000

1000

100

10

1

Mbits/s

Cat 5e 802.11b 802.11n

Cat 6 802.11g

Transmission media

Figure 14-7. Paired wiring faults. Courtesy Belden.

Reversed pair

Shorted between

pairs Shorted pair

Miswired pairs Split pairs

Px

Px Px

Px

Px

Py

Py

1

2

(^34)
Open pair