Netgear SW108 User Manual download pdf (Page 34)

Installation Guide for the Model SW108 Ethernet Switch

C-2 Cabling Guidelines

Table C-1 lists the electrical requirements of the Category 3, 4, and 5 cables.

Twisted Pair Cables

For two devices to communicate, the transmitter of each device must be connected to the

receiver of the other device. The crossover function is usually implemented internally as

part of the circuitry in the device. Computers and workstation adapter cards are usually

media-dependent interface ports, called MDI or uplink ports. Most repeaters and switch

ports are conﬁgured as media-dependent interfaces with built-in crossover ports, called

MDI-X or normal ports.

Table C-1. Electrical requirements of Category 3, 4, and 5 cables

Speciﬁcation Category 3 Category 4 Category 5

Number of pairs Four Four Two or Four

Impedance 100 Ω ± 15% 100 Ω ± 15% 100 Ω ± 15%

Mutual capacitance at 1 KHz ≤6.6 nF per 100 m ≤5.6 nF per 100 m ≤5.6 nF per 100 m

Maximum attenuation

(dB per 100 m, at 20° C) at 4 MHz: 5.6

at 10 MHz: 9.8

at 16 MHz: 13.1

at 4 MHz: 4.3

at 10 MHz: 7.2

at 16 MHz: 8.9

at 16 MHz: 8.2

at 31 MHz: 11.7

at 100 MHz: 22

NEXT loss (dB minimum) at 4 MHz: 32

at 10 MHz: 26

at 16 MHz: 23

at 4 MHz: 47

at 10 MHz: 41

at 16 MHz: 38

at 16 MHz: 44

at 31 MHz: 39

at 100 MHz: 32

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Netgear SW108 User Manual Page 34