UPGRADING REPAIRING PCs

Table 7.3 Resolving Parallel Port Problems Continued
Printers 193
Symptoms Cause(s) Solution
Switchbox between All cables and switchbox must be
device and IEEE-1284–compliant; remove
computer switchbox and connect directly to
device. If it works, replace noncompliant
switchbox or cables.
IRQ or I/O port EPP and ECP require a non-shared
address conflict IRQ; use Windows 9x Device
Manager to see whether IRQ for
LPT (parallel) port is conflicting
with another device; also check I/O
port address and DMA.
Device not Power on device before starting
powered on computer.
Port defective Use loopback and test software to verify
data going out port is readable.
Printers
Printers can be attached to your computer in a variety of ways.
Major interfaces used for printers include those listed in Table 7.4.
Table 7.4 Printer Interface Standards and Recommended Uses
Interface Type
Required Benefits Drawbacks Operating System
Parallel (LPT) Relatively fast, especially Regular printer Works with any
if EPP or ECP modes are cable length operating system.
used. Supported by restricted to
virtually any application 10 feet due to
that can print. No port signalloss. Daisyspeed
or setup options chaining with
required in most cases. other peripherals
Standard cable works with doesn’t always
virtually any PC and work. Printer must
printer combination. be last device
on daisy-chain.
Serial Standard cable can reach Serial port speed, Works with any
(RS-232/COM) up to 50 feet; use line word length, and operating system,
drivers and phone cable stop bits must be but is obsolete for
to reach hundreds of feet. set for both printer PC use.
Printer can work with and application for
terminals, PCs, or printing to work.
Macintoshes with Very slow graphics
appropriate cable. printing. Different
printers require
custom cabling.