Connecting Your Modem To The Telephone Network; Operating Your Modem - IBM Aptiva Hardware Handbook

About modems
Some IBM Aptiva PCs have a modem already installed.
Using a telephone network, a modem allows your com-
puter to communicate with other computers, fax
machines, or telephones.
Connecting your modem to the
telephone network
Modems are designed to operate over the public
switched telephone network (PSTN or PSN). This is an
analog network commonly used by most households
and businesses. Connect the modem to an analog net-
work only. If you are not sure about your telephone line,
contact your local telephone company.
• Excessive voltages can occur on telephone lines,
especially during lightning storms. To avoid any
possible damage to sensitive electronic parts,
unplug the computer and the telephone cords
during such storms.
Warning!
• Some businesses, schools, and buildings have
digital telephone systems, known as digital pri-
vate branch exchange (PBX) systems. These sys-
tems do not work with the modem. Connecting
your modem to a digital telephone system may
damage the modem.

Operating your modem

You can operate your modem either through a modem
communications software application or from your DOS
prompt.
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Most people use a communications software application
to operate their modem. Examples of these software
applications include Windows Terminal and Microsoft
Works for Windows** Terminal. These applications
allow you to operate your modem without using the
Hayes** AT command set—the commands that
modems understand. With these software applications,
you operate your modem by choosing menu items from
a screen on your computer. If you use a communications
software application, see the user's guide that came with
the software for detailed instructions on operating your
modem.
Most modem communication software applications also
note:
allow you to send specific AT commands to the modem.
You can also send commands to your modem from the
DOS (C:>) prompt. Operating your modem with DOS is
difficult and generally for experienced modem users
only. With DOS, you must type long AT command
strings and you may need to send a variety of com-
mands for each transmission. Also, you are not always
sure if your commands have been received and exe-
cuted by the modem.
To communicate with a modem from DOS, use the
ECHO command. Direct these commands to the port
your modem is connected to. For example:
This is an AT command that:
•
Stores a 0 into S register 0 to turn Auto Answer off
(ATS0=0). S registers are storage areas inside the
modem. The S registers hold values that the com-
mand set uses to control modem operations. For
and press Enter.