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

User Manual for the NETGEAR 7300S Series Layer 3 Managed Switch Software

Table 12-4. 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 12-3illustrates straight-through twisted pair cable.

Figure 12-3: Straight-Through Twisted-Pair Cable

Cabling Guidelines B-3

202-10088-01, March 2005