particular printer has two settings: draft mode
and letter-quality (LQ) mode.
PITCH BUTTON Use the pitch button to select
the number of characters to print per inch. This
particular printer has three settings: 10, 12, and
17 characters per inch.
Indicator and Warning Lights.— In looking at
figure 1-24, you will notice indicator lights located
above the control buttons on the control panel. They
provide status information and show the functions or
features currently in effect.
POWER INDICATOR The power light lets
you know that power is being supplied to the
printer.
ONLINE INDICATOR The online indicator
tells you that the printer is in online status and is
ready to receive output from the microprocessor.
While it is in this status, normally, all other panel
buttons are inoperative.
ERROR INDICATOR The error indicator
light warns you that there is a problem of some
sort that makes the printer inoperable. This
could be caused by a cover left open, the printer
out of paper, an electrical malfunction, a paper
jam, or possibly the font cartridge is not in place
or is improperly seated.
FONT, PRINT MODE, AND PITCH
INDICATOR LIGHTS The lights located
above each button and next to each feature tell
you the current operating modes of the printer.
The lights are lit next to selected features.
Accessories and Other Hardware
In addition to monitors, disk drives, keyboards, and
printers, you may find a number of other attachments to
microcomputer systems. These might include a mouse
device, cassette tape drive, optical scanner, CD-ROM
drive, switch box, modem, and so on.
MOUSE DEVICE.— You may have a mouse
device attached to your micro. It allows you to freehand
sketch or to select items from menus on the display
screen. As you move the mouse, the cursor moves to a
corresponding location on the display screen. For
example, if you are selecting an item from the menu,
you move the cursor to the item and press a button on the
mouse to select the item.
TAPE DRIVE.— You can use cartridge or cassette
tapes to provide backup to the hard drive. The tape drive
may be internal or external to the system unit. A tape
drive makes a good, reliable backup system for the
micro, since it holds 60MB or more of data. If a tape
drive is not available, you can backup to floppy disks.
OPTICAL SCANNER.— An optical scanner can
be used to scan (read) graphic art or text directly into the
microcomputer. This saves redrawing or retyping.
CD-ROM DRIVE.— You may have a CD-ROM
(compact disk-read only memory) drive to read data
stored on compact disks. CD-ROM technology is the
same as that used for audio disks, except it includes
routines for detection and correction of data errors. The
CD-ROM drive can be internal or external to the system
unit. Compact disks can hold a vast amount of
information, 550MB or more. They are used when the
same information is needed by many, and the
information is fairly constant. For example, libraries
can put all the information they need about documents
and publications on a CD-ROM. On a CD-ROM, the
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