IBM Aptiva Handbook

152 Appendix C: Modem information
The dialing sequence you type on your computer might
look like this: *70,,,5554343. The commas (,,,) pause
the modem until the command is carried out, then the
telephone number is dialed automatically.
Call Waiting will be disabled only
for the duration of
your modem’s current call and only from the calling end.
For incoming calls, you may find it helpful to change the
value of register S10 to a higher number. For more
information on S registers, see “S registers” on
page 174.
Your modem communications software determines how
your modem operates with Call Waiting. For specific
instructions, see the documentation or online help that
came with the communications software.
If your computer came with fax software already
installed, the fax software documentation was included
in the box your computer came in.
How modems work
Modems are classified into two functional categories:
data modems and fax modems. Data modems can
communicate with other data modems, and fax
modems can communicate with other fax modems.
Some data modems can also function as fax modems.
The modem in your Aptiva computer is a data modem
that also works as a fax modem.
Data modems
Data modems send and receive data in the form of
codes that represent individual letters, numbers, and
spaces. This data travels in a stream, one character right
after another. Special programs, like word processors,
use additional code sequences to indicate font type,
bold, italic, and other text attributes.
You use the Attention command set (sometimes called
the AT or Hayes command set) to send commands to
your data modem. The ATcommand set, default
modem settings, and many of the more sophisticated
modem commands have evolved over the years.
Fax modems
Fax modems send and receive images of what is
displayed or printed on a page. As long as the text and
pictures on the page are displayed or printed in black
and white, without variations of gray or addition of
color, a receiving fax modem can fairly accurately
reproduce the image sent by the sending fax modem.
A sending fax machine, as well as fax software that
works with word processing programs, scans a page
one line at a time, breaking the page down into
hundreds of lines. Each line is translated into a series of
dots. Black dots represent the areas of the page that
contain a piece of an image. White dots represent blank
areas on the page. These dots are then converted into
codes that can be sent through telephone lines to other
fax machines or computers.

IBM Aptiva Specifications

General

Brand	IBM
Model	Aptiva
Category	Desktop
Language	English