NETGEAR SW108 manual Twisted Pair Cables, Specification Category

Installation Guide for the Model SW108 Ethernet Switch

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

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 4 MHz: 4.3		at 16	MHz: 8.2
	at 10 MHz: 9.8		at 10 MHz: 7.2		at 31	MHz: 11.7
	at 16	MHz: 13.1	at 16	MHz: 8.9	at 100 MHz: 22
NEXT loss (dB minimum)	at 4 MHz: 32		at 4 MHz: 47		at 16	MHz: 44
	at 10	MHz: 26	at 10	MHz: 41	at 31	MHz: 39
	at 16	MHz: 23	at 16	MHz: 38	at 100 MHz: 32

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.

C-2 Cabling Guidelines