Information Technology Reference
In-Depth Information
10/100/1000 BaseT switch hub
High-speed
uplink port to
backbone switch
Switched
packet to only
one hub port or
to uplink port
Original packet
transmitted
from this
workstation
FIGURE 2.3
In switched 10/100/1000BaseT, a transmission by a station first goes to the hub, where it is
switched to a single port attached to the destination station.
Although 10/100BaseT uses only two wire pairs, it is customary to use 4-pair
cable to make the station drops. Several of the 100 Mbps network schemes require
all four pairs. In addition, a jack that is wired for all four pairs can support many
other types of data and voice connections, which may use some other combination
of the eight connector pins.
Some installations use the other two pairs for a telephone connection or for
another 10/100BaseT connection. Be wary of telephone installers “stealing” your
network wiring pairs for their use. Telephone wiring is often at cross purposes from
network wiring. The standards are different, as are the installation practices.
10/100BaseT and Structured Wiring
The TIA/EIA-568-C wiring standard supports 10/100BaseT wiring. The wiring
standards of Category 3 are normally adequate if you only need 10BaseT speeds,
although you may wish to use Category 5e or 6 in a new installation to allow for
future enhancements. 100BaseT requires Category 5 or greater to run its rated dis-
tances, although it may be able to operate for shorter distances on a lower category
of cable.
