Hardware Reference
In-Depth Information
a D-shaped 15-pin connector called a DB-15 (for Thicknet coaxial cables). Some older
10Mbps adapters have a combination of two or all three of these connector types; ad-
apters with two or more connectors are referred to as
combo adapters
. Token-Ring ad-
apters can have a 9-pin connector called a DB-9 (for Type 1 STP cable) or sometimes an
8P8C (RJ-45) jack (for Type 3 UTP cable).
Figure 17.4
shows all three of the Ethernet
connectors.
Figure 17.4
Three Ethernet connectors on two NICs: Modern 8P8C (RJ-45) connector (top center), Obsol-
ete DB-15 connector (bottom right), and Obsolete BNC connector (bottom left).
Note
Although RJ-45 is the common name for the UTP Ethernet connector, this is a misnomer.
Thecorrectnamefortheconnectoris8P8C,whichindicatesan8-pin,8-conductorconnector.
The actual RJ-45S connector is an eight-position connector but is used for telephone rather
than computer data. An RJ-45S jack has a slightly different shape than the connector used
for Ethernet, and it includes a cutout on one side to prevent unkeyed connectors from being
inserted into it.
For drawings of the true RJ-45S jack and other telephone jacks, see
www.siemon.com/us/
Ethernet NICs made for client-PC use on the market today are designed to support un-
shielded twisted-pair (UTP) cable exclusively. Cards using BNC or DB-15 connectors
would be considered obsolete.
