Dell 2100/200, 2100/180 manual Ports and Connectors, Serial and Parallel Ports

I/O Ports and Connectors

The I/O ports and connectors on the back panel of the computer are the gateways through which the computer system communicates with external devices, such as a keyboard, mouse, printer, and monitor. Figure B-2 identi- fies the I/O ports and connectors for your system.

Serial and Parallel Ports

The two built-in serial ports use 9-pin D-subminiature con- nectors 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 default designations of your computer’s built- in serial ports are COM1 and COM2. COM1 is the bottom connector; COM2 is on the top.

The built-in parallel port uses a 25-pin D-subminiature con- nector on the computer’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 parallel port (for example, LPT1). The default designation of the computer’s built-in parallel port is LPT1.

Port designations are used, for example, in software installation procedures that include a step in which you identify the port to which a printer is attached, thus tell- ing the software where to send its output. (An incorrect designation prevents the printer from printing or causes scrambled print.)

KYBD (left)

MOUSE (right)

SERIAL

COM 1(left)

SERIAL

COM 2 (right)

PARALLEL

LPT 1

VIDEO

JVGA

Figure B-2. I/O Ports and Connectors

Hardware Configuration Features B-125