NETGEAR ETHERNET SWITCH SW108 - Manual (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
SW108.BK Page 2 Friday, June 27, 1997 10:48 AM