Hardware Reference
In-Depth Information
Legacy Parallel Port
Parallel ports, like serial ports, are mostly obsolete nowadays, and hence have the
word
legacy
associated with them. They were used for connecting printers prior to the
popularization of USB. Although technically they can be used for other device types, parallel
ports became so closely associated with printing that alternative names for the parallel port
include
printer port
and
LPT (line printer) port
. Figure 4.23 shows a DB25F parallel
port. (Remember, DB refers to the D-shaped ring, 25 is the number of pins, and F means
there are holes rather than pins.)
FIGURE 4.23
A parallel connector
Network and Modem Ports
Ethernet networks use the RJ-45 connector standard, as you learned in Chapter 3. The
jacks on the PC look like wide telephone jacks. Figure 4.24 shows a modem jack (regular
telephone connector, RJ-11 or RJ-14) and a network jack (RJ-45) for comparison.
FIGURE 4.24
Modem (left) vs. Ethernet (right)
As you learned in Chapter 2, there are always-on broadband modems available today for
cable and DSL service. However, the modem jack in Figure 4.24 is for a dial-up modem via
regular telephone service (the very slow kind of connection that nobody uses anymore for
Internet service if they have any alternative available).
