Installation Guide for the Model FS509 Fast Ethernet Switch
C-2
Cabling Guidelines
•
295 feet (90 meters) from the wiring closet to the wall outlet
•
10 feet (3 meters) from the wall outlet to the desktop device
The patch panel and other connecting hardware must meet the requirements for 100 Mbps
operation (Category 5). Only 0.5 inch (1.5 cm) of untwist in the wire pair is allowed at any
termination point.
Category 5 Cable Specifications
Table C-1 lists the electrical requirements of Category 5 UTP 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.
Table C-1.
Electrical Requirements of Category 5 Cable
Specification
Category 5 Cable
Number of pairs
Four
Impedance
100
Ω
±
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
