Twisted pair cables, Twisted pair cables -3 – NETGEAR 7300 Series User Manual

Page 337

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

Cabling Guidelines

B-3

202-10009-01_060204

Table 13-3.

Electrical Requirements of Category 5 Cable

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 13-1

illustrates straight-through twisted pair cable.

Figure 13-1: Straight-Through Twisted-Pair 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

(dB per 100 m, at 20° C)

at 4 MHz: 8.2
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

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