Hardware Reference
In-Depth Information
connector that can be found on some printers. Most parallel ports use the standard Type A receptacle.
The three connectors are shown in
Figure 14.25
.
Figure 14.25. The three types of IEEE 1284 parallel port connectors.
The IEEE 1284 parallel port standard defines five port-operating modes, emphasizing the higher-
speed EPP and ECP modes. Some of the modes are input only, whereas others are output only. These
five modes combine to create four types of ports, as shown in
Table 14.16
.
Table 14.16. Types of IEEE 1284 Ports
The 1284-defined parallel port modes are shown in
Table 14.17
,
which also shows the approximate
transfer speeds.
Table 14.17. IEEE 1284 Parallel Port Modes
Each of the port types and modes is discussed in the following sections. These modes can be selected
via the BIOS Setup in motherboards with built-in parallel ports.
Standard Parallel Ports
Older systems did not have different types of parallel ports available. The only available port was
the parallel port that was used to send information from the computer to a device such as a printer.
The unidirectional nature of the original PC parallel port is consistent with its primary use—that is,
