NETGEAR L3 manual Twisted Pair Cables, Specifications Category 5 Cable Requirements

7000 Series L3 Managed Switch Reference Manual for Software v2.0

Table 10-1. Electrical Requirements of Category 5 Cable

SPECIFICATIONS	CATEGORY 5 CABLE REQUIREMENTS
Number of pairs	Four
Impedance	100 ± 15%
Mutual capacitance at 1 KHz	5.6 nF per 100 m
Maximum attenuation	at 4 MHz: 8.2
(dB per 100 m, at 20° C)	at 31	MHz: 11.7
	at 100 MHz: 22.0
NEXT loss (dB minimum)	at 16	MHz: 44
	at 31	MHz: 39
	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. Auto Uplink technology automatically senses which connection, MDI or MDI-X, is needed and makes the right connection.

Figure A-1illustrates straight-through twisted pair cable.

Figure A-1: Straight-Through Twisted-Pair Cable

Cabling Guidelines A-3