IBM Aptiva Personal Computer
(250-0451A) Modems Faxback Doc. # 33153
Some IBM Aptiva PCs have a modem already installed. Using a telephone
network, a modem allows your computer 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 network ONLY. If you are
not sure about your telephone line, contact your local telephone company.
WARNING: 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.
Some businesses, schools, and buildings have digital telephone
systems, known as digital private branch exchange (PBX) systems.
These systems 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.
Most people use a communications software application to operate their
modem. Examples of these software applications include Hyper 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.
NOTE: Most modem communication software applications also 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 commands for each transmission. Also, you
are not always sure if your commands have been received and executed 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:
C:\ > echo ATSO=0&W0W1>COM1 and press Enter.
This is an AT command that:
Stores a 0 into S register 0 to turn Auto Answer off (ATSO=0). S
registers are storage areas inside the modem. The S registers hold
values that the command set uses to control modem operations. For
more information on S registers, see page 34.
The &W0&W1 portion of the command stores ATSO=0 into memory (NVRAM
locations 0 and 1) for future use.
The command is directed to the modem's port (>COM1).
Whether you use DOS or a modem communications software application, you can
send a wide variety of commands to your modem. For a detailed listing of
modem commands see page 30.
Tips on using your modem
This section provides tips on:
Using the Auto Answer feature with your modem communications software
Using the telephone with your modem
Using the Auto Answer feature
If you use a modem communications software application, it may require
your modem to be set for Auto Answer. The Auto Answer feature lets your
computer answer calls from another computer automatically.
Your modem communications software determines how the modem operates with
Auto Answer. Some fax applications do not require you to type an AT
command to turn Auto Answer on or off. For specific instructions, see the
user's guide that came with the communications software.
To start the Auto Answer feature from your communications software, use
the command: ATSO=n. This command tells the modern to answer a call after
a certain number of rings. To set the number of rings, replace n with any
number from 1 to 255.
Turn Auto Answer off when you are not using your modem. Otherwise, callers
will be greeted with the modem tone. To turn Auto Answer off, use the
command: ATSO=0.
If your computer came with fax software already installed, use the fax
software documentation included in the box your computer came in or the
fax software in the box your computer came in or the fax software online
Help for additional information.
Using the telephone with your modem
While you are using the modem, do not pick up any telephone receiver on
that line. If you do, communications will be interrupted.
Disabling Call Waiting
If you use Call Waiting, you may want to disable it while using your modem.
With Call Waiting, communications can be interrupted when a second call is
waiting to be answered.
To disable Call Waiting, contact your telephone company. Different
telephone companies have different procedures for disabling this feature.
Also, some telephone companies cannot disable Call Waiting. Your telephone
company business office should be able to tell you the procedures and
dialing sequence required to disable Call Waiting.
A dialing sequence is similar to a command you type on your computer. For
example, in some areas the following dialing sequence disables Call
Waiting:
(# or *) 70,,,(complete telephone number)
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 page 34.
Your modem communications software determines how your modem operates with
Call Waiting. For specific instructions, see the user's guide 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
If you are having problems connecting to other modems, or are interested in
learning more about how modems work, the information in this section can
help you. This section discusses the modem connection process, data
modems, connecting to other data modems, fax modems, and choosing fax
software applications.
Modem connection process
For two modems to connect, they must be of the exact same type and
function. A data modem can only connect to a data modem and a fax modem
can only connect to a fax modem. Many modern modems are designed with both
data and fax capabilities. The data components of these data/fax modems
can communicate with data modems, and the fax components can communicate
with fax modems.
The connection process is controlled by software built into the modem.
This connection process is called a protocol. Modems communicate by
protocol and negotiate to achieve a connection. These protocols must be
compatible for the modems to connect.
The result of this negotiation determines the speed at which the two modems
connect. For example, a 14,400 bits per second (bps) modem connects with a
9,600 bps modem at the lower speed of 9,600. But, because of phone line
noise, they may connect at 2,400 bps. If you use a modem communications
software application (such as Windows Terminal or Microsoft Works for
Windows), you should see the final connection speed on the screen. This
rate remains constant throughout the session.
Data modems
Data modems send and receive data in the form of codes that represent
letters, numbers, and spaces. Each letter of a word is represented by a
code. These codes are sent in a series with a different code represent a
space between words. Special applications, like word processors, use
additional code sequences to indicate font type, bold, italic, and so on.
You use the Attention command set (sometimes called the AT or Hayes command
set) to send commands to your data modem. The AT command set has evolved
over the years, and some of its "standards" have also changed. Modem
default settings and the more sophisticated modem commands, in particular,
have changed over time.
Modem protocols govern the way a modem converts digital information from
the computer into analog signals that can be transmitted over the telephone
lines. Over time, standards have been created for these protocols. These
standards are necessary so that modems made by different companies can
exchange data.
Primarily, modern standards and recommendations in the United States have
been set by two organizations:
The International Telephone and Telegraph Corporation set the Bell
standards.
The International Consultative Committee on Telephony and Telegraphy
(CCITT) set the V. (Vee Dot) recommendations.
Data modems use these standards for speeds up to 28,800 bps:
Bell 103
Bell 212A
CCITT V.21, V.22, V.22bis, V.23, V.32 V.32bis, and V.34.
Many modems support all of these standards. Older modems may support some,
but not all of these standards.
Connecting to other data modems
Phone line noise can cause loss of data and connection when modem speeds
rise above 1200 bps. Over time, many different software transmission
protocols, such as X-modem, MNP, and V.42bis, have been developed solely
to detect and correct the errors caused by phone line noise. Not all of
these protocols are compatible. This may be the reason you are unable to
connect to another modem.
If your data modem uses any error detection and correction protocol, the
modem on the other end must also have the same protocol. For example, if
your data modem uses X-modem (one of the early protocols), the modem you're
connecting to must also use X-modem. This is why you are asked to choose a
transfer type in your software before downloading a file from a bulletin
board.
Many different error detection and correction protocols are commonly used
today. Examples of the earliest error detection and correction protocols
include X-modem, Y-modem, and Kermit. These protocols are performed by
software on your computer.
Recently developed protocols include the Microcom Network Protocol (MNP)
and V.42bix. These protocols are performed by microcode. Microcode is
software built into the modem. V.42bix is the newer of these two
protocols. It has its own methods of error detection and correction, and
also incorporates the MNP 4 and 5 and modems with V.42bis can connect with
each other.
If you cannot connect to another modem, it may be because the protocol you
are using is not compatible with the protocol of the modem on the other
end. If you're having trouble connecting to other modems, try following
these guidelines.
If you know what protocols are available on the modem you are
connecting to, enable a protocol on your modem that is supported by the
other modem. Usually V.42bis works best if both modems support it.
If you frequently connect to bulletin boards, you should buy a modem
communications software application that includes many different
software protocols. Different bulletin boards use different protocols.
Many network services have their own proprietary protocols. To connect
to these services, you often have to buy the protocol from the service.
Other network services rely on V.42bis or MNP 4 and 5.
Important: All error detection and correction protocols compress data to
avoid slowing the transmission rate. However, combining
protocols will not increase your transmission speed or
significantly reduce transmission errors.
For example, running V.42bis and X-modem together will not give
you a greater compression rate or transmission speed than
running V.42bis alone. Use only one protocol.
Fax modems
Fax modems send and receive facsimiles and generally transmit and receive
pictures better than text or other data. In a fax machine, a page is read
by a scanner and broken into a series of dots representing light and dark
portions of the page. These dots compose the pictures, graphics, letters,
and numbers printed by the fax machine.
Important: The scan rate option in your fax software determines the size
of a fax and how much time it takes to transmit the file.
The fax machine scans a page line-by-line and records the number and
position of each dot in a scan line. This information is converted into a
special code and transmitted to another computer or fax machine. This
transmission uses a set of transfer and modulation specifications called
protocols.
Fax machines and modems are connected in Groups. The Group a fax machine
belongs to indicates its speed and level of technological advancement. The
original fax machines were Group 1 machines. These are the slowest
machines and are almost obsolete today. Faster Group 2 fax machines
replaced the Group 1 machines. Group 2 machines are also nearly obsolete
today. Most fax machines sold today are Group 3 machines.
Generally, a Group 3 fax machine can connect most efficiently to another
Group 3 machine and may also be able to connect to many Group 2 machines.
However, a Group 2 machine cannot connect to a Group 3 machine. The modem
in your computer works with most Group 3 fax machines but not Group 2 or
group 1 fax machines.
Choosing fax software applications
If your computer did not come with fax software, you must buy a fax
software application to operate your fax modem. Also, if you add a fax
modem to your computer, you need to purchase fax software.
You send commands to a fax modem (or the fax portion of a data modem) using
a revised version of the AT command set. This revised version includes two
different sets of commands: Class 1 and Class 2. Some modems support one
class of command while others support both. When buying a fax software
application, choose the highest class that your modem supports. The modem
in your computer supports class 2 fax machines.
NOTE: CAS and SENDFAX are two other commonly used command sets. These
command sets are not supported by the modems already installed in
IBM Aptiva PCs.
Communications settings
The modems already installed in IBM Aptiva PCs are preset to COM 1 SERIAL
PORT 1. The addresses and interrupts supported by your computer are:
COM # Address Interrupt
COM1 3F8 IRQ 4
COM2 2F8 IRQ 3
COM3 3E8 IRQ 4
COM4 2E8 IRQ 3
Changing modem addresses for the Mwave adapter card
The modem address in your communications software must match the address
setting of your modem. To change the modem address settings, following
these steps:
1. If you are using OS/2 Warp, double click on the Mwave for OS/2 icon on
the OS/2 desktop.
If you are using Microsoft Windows, double-click on the Mwave icon on
the Program Manager screen.
2. Double-click on the Hardware Configuration icon.
3. Click on the down arrow in the "COM #" box of the "Modem/FAX" item.
NOTE: If you accidentally click on the wrong box, press Esc. The box
will close and you can try your selection again.
4. Double-click on the COM number that you want your modem to use.
NOTE: When you click on a COM number the I/O address and IRQ settings
will be updated automatically.
5. Click on Update. A "Confirm" window appears. When you have read the
contents, click on Yes.
6. An "Information" window will be displayed. When you have read the
contents, click on OK.
7. Click on Exit to exit the Mwave Hardware Configuration utility. You
must re-boot your computer for these changes to take effect.
8. If you are using OS/2 Warp, close all open programs. Click on the
Shut down button, then click on OK.
When you see the message to press Ctr, Alt, and Delete, turn the
computer off.
If you are using Microsoft Windows, close all open programs. From the
"File" menu on the Program Manager screen, click on "Exit Windows".
Click on OK.
At the "Aptiva Menu" turn the computer off.
Changing modem addresses for non-Mwave adapter cards
If you purchased a computer that does not have Mwave modem support or if
your computer has a non-Mwave modem, refer to the documentation that came
with the modem for instructions on changing modem addresses.
(br/all-06/03/96)
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