I/O Ports And Connectors; Serial And Parallel Ports; Adding An Expansion Card Containing Serial Or Parallel Ports; Figure B-2. I/O Ports And Connectors - Dell Precision 410 User Manual

I
/O Ports and Connectors
The I/O ports and connectors on the back panel of your
computer are the gateways through which your 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 computer.

Serial and Parallel Ports

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 transmis-
sion of data one bit at a time over one line).
Most software uses the term COM (for COMmunica-
tions) 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.
The built-in parallel port uses a 25-pin D-subminiature
connector 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.
parallel port
mouse
connector connector
serial port 1
connector

Figure B-2. I/O Ports and Connectors

video connector (may be in bottom
or second expansion slot)
keyboard
connector
NIC connector
USB connectors
Most software uses the term LPT (for Line PrinTer) plus a
number to designate a parallel port (for example, LPT1).
The default designation of your computer's built-in paral-
lel 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 your printer is attached, thus
telling your software where to send its output. (An
incorrect designation prevents the printer from printing
or causes scrambled print.)
Adding an Expansion Card Containing
Serial or Parallel Ports
Your computer system has an autoconfiguration capabil-
ity for the serial ports. This feature lets you add an
expansion card containing a serial port that has the same
designation as one of the built-in ports without having to
reconfigure the card. When the computer detects the
duplicate serial port on the expansion card, it remaps
(reassigns) the built-in port to the next available port
designation.
Both the new and the remapped COM ports share the
same IRQ setting, as follows:
COM1, COM3: IRQ4 (shared setting)
COM2, COM4: IRQ3 (shared setting)
serial port 2
connector
microphone jack
Hardware Configuration Features
line-out jack
line-in
B-5