User guide

support.dell.com I/O Ports and Connectors B-1

    
This file provides specific information about the input/output (I/O) ports and connec-
tors on the back panel of the computer system.
The I/O ports and connectors on the back panel of the system are the gateways
through which the computer system communicates with external devices such as a
keyboard, mouse, printer, and monitor. Figure B-1 identifies the I/O ports and connec-
tors for your system.

The two built-in serial ports use 9-pin D-subminiature connectors on the back panel.
These ports support devices such as external modems, printers, plotters, and mice
that require serial data transmission (the transmission of data one bit at a time over
one line).
Most software uses the term COM (for communications) plus a number to designate
a serial port (for example, COM1 or COM2). The defaults for your system's built-in
serial ports are COM1 and COM2.
The built-in parallel port uses a 25-pin D-subminiature connector on the system's back
panel. This I/O port sends data in parallel format (where eight data bits, or one byte,
are sent simultaneously over eight separate lines in a single cable). The parallel port is
used primarily for printers.
Most software uses the term LPT (for line printer) plus a number to designate a paral-
lel port (for example, LPT1). The default for the system's built-in parallel port is LPT1.