This chapter describes how to install and use modems with Windows 95, and the other communications tools in Windows 95, including HyperTerminal, Phone Dialer, and Microsoft File Transfer.
Modems and Communications Tools: The Basics
Modems and Communications Tools: The Issues
Telephony Drivers from Other Vendors
Troubleshooting Communications Problems
Modems and Communications Tools: The Basics
u Support for hundreds of brand-name modems, including automatically detecting them
u Modem connections and configuration using point-and-click instead of AT commands
Windows 95 includes three tools for expanding communications capabilities:
u Microsoft File Transfer allows you to send and receive files while talking on the phone.
With Windows 95, you can do the following:
u Send and receive faxes over a modem using Microsoft Fax. For more information, see Microsoft Fax.
u Configure HyperTerminal to predefine computers to which your computer can connect.
u Configure Phone Dialer to make voice telephone calls.
u Manually dial a phone call or display a terminal window before or after dialing.
Modems and Communications Tools: The Issues
Before you install and configure a modem for use with Windows 95, you should decide the following:
You can install a new modem in one of three ways:
u Running a communications application, which causes Windows 95 to prompt you to install a modem
u Adding a modem through the Add New Hardware option in Control Panel
In all cases, the Install New Modem wizard appears, and asks if you want Windows 95 to automatically detect the modem or if you want to manually select a modem from the list of known manufacturers and modem models. If you choose the detection option, the wizard detects and then queries the modem to configure it. If it cannot detect the modem, it prompts you to select one.
When the modem has been selected, you can, if necessary, adjust its properties, such as the volume for the modem speaker, the time to wait for the remote computer to answer the call, and the maximum speed to use.
Depending on the type of modem you have, installing and configuring it might vary slightly as follows:
u If you are using Windows 95 PCMCIA drivers, then Windows 95 will detect and configure PCMCIA modem cards automatically when they are first inserted. Otherwise, you might need to run the Add New Hardware wizard in Control Panel to configure the cards built-in COM port. Then, you should install the PCMCIA modem card by using the Modems option in Control Panel. For more information, see Devices.
Before you install a modem, check the Modems section in the Windows 95 README.TXT for possible information.
Û To install a modem by using the Modems option in Control Panel
2. If no modem is currently installed on your computer, the Install New Modem wizard starts automatically to lead you through the steps for installing a modem. Follow the online instructions.
Or
If you are installing a second modem, click Add to start the Install New Modem wizard.
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In most cases, its best to let the Install New Modem wizard detect the modem for you. If it cannot detect the exact manufacturer and model, the wizard picks a standard configuration that is usually compatible. Your modem will still function at its maximum speed and according to factory default settings. A few advanced features might be disabled, such as enabling and disabling compression, error control, and flow control.
For information about installing a modem if your modem is not detected or listed, or about finding a better match than the standard modem.
Windows 95 automatically assigns COM names to communications ports, internal modem adapters, and PCMCIA modem cards according to their base I/O port addresses as described in Devices.
The first time you set up a modem, the Install New Modem wizard prompts you for information about the location you will usually be calling from (the Default Location), including your area code and country code. This information is stored in Dialing Properties, a communications utility that is accessible from all communications applications created for Windows 95 and in the Modems option in Control Panel.
Û To set dialing location information
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After you install the modem, more specific location information, such as calling card numbers or the number you must dial to access an outside line, can be entered into the My Locations dialog box in Dialing Properties.
Setting Modem Properties
In the Modems option in Control Panel, you can globally change default modem settings for all communications applications and tools created for Windows 95. For example, if you do not want to listen to the modem speaker, you can turn it off for all tools and applications that use that modem. Alternatively, you can adjust these settings within each application.
For Windows 3.1 based or MS-DOS based applications, you need to configure the modem settings within each application.
Û To view general properties for a modem
2. In General properties, view the default settings for the modem that will be used by all applications created for Windows 95.
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Option | ||
Port | ||
Speaker volume | ||
Maximum speed | Set the speed lower if the faster rate causes data errors. Set it higher for faster performance if you are using a computer with an 80486 or a Pentium™ processor. For example, 57600 might work better than the Windows 95 default setting of 38400 for v.32bis (14400 bps) modems on fast computers. If applications report data errors, then set a lower speed (for example, change it from 38400 to 19200 for v.32bis modems). |
If you have a slower, older computer and an external modem, you can purchase and install a 16550A UART-based COM port adapter to increase speeds. Some internal modems have an integrated 16550A UART adapter.
Û To change or view the connection properties
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Option | ||
Connection preferences | ||
Wait for dial... | ||
Cancel the call... | ||
Disconnect a call... |
You can also specify settings for data bits, parity, and stop bits in the Connection properties. For information about these values, see online Help.
Û To view or change advanced connection properties
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Option | ||
Use error control | ||
Required to connect | ||
Compress data | ||
Use cellular protocol | ||
Use flow control | ||
Low-speed modulation | ||
Extra settings | ||
Record a log file |
Dialing Manually
Windows 95 allows you to manually dial your modem if you are having difficulty making an international call or other connection. To manually dial your modem, you need a separate telephone headset and keypad. You can request manual dialing, using slightly different procedures from within any Windows 95-based communications applications, such as HyperTerminal, Dial-Up Networking, or Microsoft Fax. The following procedure describes how to manually dial your modem by using Dial-Up Networking.
Û To manually control modem dialing
2. Click the Configure button, and then click the Options tab.
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4. Double-click the connection icon in Dial-Up Networking, and then click Connect.
5. When instructed, pick up the phone and dial the number.
6. When you hear the other computer answer, click Connect and hang up.
Displaying the Terminal Window
Before or after dialing, you can display a terminal window to type AT modem commands if a connection requires them. A terminal window can be used to log on for security purposes, to establish connections with servers that require a specific logon procedure, and for other reasons. The following procedure describes this process for Dial-Up Networking.
Û To display a terminal window before or after dialing
2. Click the Configure button, and then click the Options tab.
3. Click the Bring Up Terminal Window Before Dialing option, or the Bring Up Terminal Window After Dialing option, and then click OK.
Modem Registry keys are stored under the following key:
Hkey_Local_Machine\System\CurrentControlSet\Services\Class\Modem
Value | ||||||
00 | ||||||
01 | ||||||
02 | ||||||
03 | ||||||
08 | ||||||
09 | ||||||
0A | ||||||
0B |
Bits per second | ||
2400 | ||
9600 | ||
14400 | ||
19200 | ||
28800 |
You can use HyperTerminal with a modem to connect two computers so you can send and receive files or connect to computer bulletin boards and other information programs. For example, you can use HyperTerminal to connect to an online service and to download files from a bulletin board on the online service. You can also use HyperTerminal to connect a computer directly to another computer, such as a debugging terminal.
The easiest way to install HyperTerminal is to choose Custom setup type during Windows 95 installation and then select HyperTerminal when selecting components to install.
Û To install HyperTerminal after Windows 95 Setup
2. In the Windows Setup Components list box, click Communications, and then click the Details button.
3. In the Communications dialog box, click HyperTerminal, and then click OK.
For more information, see the online Help in HyperTerminal.
HyperTerminal supports the following file transfer protocols.
HyperTerminal supports the following terminal emulation types.
Û To choose a terminal emulation type
2. In the connections properties, click the Settings tab, and then select the emulation type.
The Phone Dialer application that comes with Windows 95 allows you to use a computer to make voice telephone calls using the calling card and location information defined in Dialing Properties. It also stores frequently dialed numbers, dials stored phone numbers, and logs telephone calls.
The easiest way to install Phone Dialer is to choose Custom Setup during Windows 95 installation and then follow the following procedure. You can also install it after Windows 95 installation in the Add/Remove Programs option in Control Panel.
Û To install Phone Dialer after Window 95 installation
2. In the Windows Setup Components list box, click Communications, and then click the Details button.
3. In the Communications dialog box, click Phone Dialer, and then click OK.
Û To start Phone Dialer and make a call
2. In the Phone Dialer dialog box, type a phone number either from your keyboard or use the Phone Dialer numeric keypad. Click Dial.
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When you dial a number with Phone Dialer, the number is automatically stored in a list of your most recently used telephone numbers. All local, domestic long-distance, or international telephone numbers are stored when you type all the digits needed to dial in the Number To Dial text box. You can also store phone numbers as speed-dial numbers.
The Number To Dial text box can hold as many as 40 digits. Therefore, you can type a local, domestic long-distance, or international long-distance phone number in this text box. The same is true when you create speed-dial numbers.
If you type the area code and local telephone number, Phone Dialer automatically precedes the dialed number with a "1" if you have typed this information in the My Locations properties in the Dialing Properties dialog box. Dialing Properties is a separate communications tool.
If you type nonnumeric characters (such as a hyphen or a parenthesis) in a phone number, Phone Dialer ignores them except when you type a plus sign (+) at the beginning of your number, which is international format. If you type a number in international format, you must put parentheses around the area code, for example, +1 (206) 882-8080.
For more information, see the online Help in Phone Dialer.
According to the North America Dialing Plan (a standard set of procedures that telephone companies in North America use), you must dial a "1," followed by a three-digit area code, followed by a seven-digit local phone number to make a long-distance call. There are a few cases where local phone companies have not followed this rule by allowing you to omit the initial "1" for certain numbers in adjacent area codes. Thus, the number you dial is 10 digits, not 11.
Û To dial long-distance calls without a "1" prefix
2. Verify that the area code listed here is correct for your location. (Change it if necessary.) Click OK.
3. Using any method you prefer for storing phone numbers, type the phone number as a 10-digit number, omitting the "1" prefix.
The Windows 95 telephony number translation function sees the local area code in both the location and in the destination number, and assumes it should dial only the local number. For example, suppose you are dialing from area code 905 and can dial phone numbers with area code 416 without the "1" prefix. You would store those numbers as +1 (905) 416xxxxxxx where xxxxxxx is the local phone number.
Using Dialing Properties
Dialing Properties is a utility that has been integrated with Phone Dialer, HyperTerminal, Dial-Up Networking, and other communications applications created for Windows 95.
The options you set with Dialing Properties are stored in the TELEPHON.INI file (instead of the Registry) to ensure backward compatibility with older 16-bit Windows telephony-enabled applications.
With Dialing Properties, you can do the following:
u Define calling card rules
In Windows 95, you can access Dialing Properties from the Tools menu in Phone Dialer, or by clicking the Dialing Properties button when you make a new connection in HyperTerminal. For purposes of discussion, procedures in this section describe accessing Dialing Properties from Phone Dialer.
Defining Calling Locations
A location is information that Dialing Properties uses to analyze telephone numbers in international format, and to determine the correct sequence of numbers to be dialed. It need not correspond to a particular geographic location, but it usually does. For example, a location could specify the procedures needed to dial calls from your office, or from a room in a hotel. You can name locations anything you choose to help you remember and select them later. Dialing Properties allows you to add new locations, edit existing locations, and remove locations you no longer need.
Û To define a location in Dialing Properties
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u Area code
u Name of country
u Access number required to make a local or long-distance call
u Whether your phone has call waiting and whether it should be disabled
u Whether your phone uses pulse or tone dialing
u Whether you use a calling card to make calls
3. If you want to change calling card information, click the Change button.
Defining Calling Card Rules
A calling card is information that Dialing Properties uses to create the sequence of numbers to be dialed on a particular call. The calling card can include a calling card number that can be dialed at a specified time during call placement. However, the calling card does not have to specify a card number (in other words, calling cards can also be used to define alternative procedures for direct dialing without a calling card number). To help you remember them, you can name calling cards anything you choose.
Dialing Properties includes predefined settings for several popular calling cards, including AT&T®, Sprint, MCI, British Telecom, France Telecom Mercury, Telecom New Zealand, and others. You can modify and use these directly or copy them to create your own calling cards. Dialing Properties allows you to add new calling cards, edit existing calling cards, and remove calling cards you do not need.
The information stored in a calling card includes the name, card number, and the dialing rules for local, long-distance, and international calls.
Û To specify that you are using a calling card in Dialing Properties
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You can also customize dialing rules by clicking the Advanced button in the Change Calling Card dialog box. The following two examples illustrate how you might use dialing rules.
If you are making a calling-card phone call from outside the United States and do not want Windows telephony applications to automatically add a "0" prefix to the number you are calling, precede the phone number with another numeric code, such as "144" in the following example.
Û To redefine numbers that automatically precede the phone number
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Code | ||
E | ||
F | ||
G | ||
H | ||
W | ||
@ | ||
$ | ||
? |
Option | ||
Calls within the same area | ||
Long-distance calls | ||
International calls |
4. Using Phone Dialer or HyperTerminal (or another tool), store your destination number in international format with only the country code (44), area code (without the leading 0), and local number (+44(71)5551212).
When you choose the Dial option from Phone Dialer or HyperTerminal, the tool you are using automatically expands this number to include "144" and the card number, plus the pause codes.
In another scenario, suppose your organization in the United States uses a PBX system and you need to omit the "1" prefix before the area code. Create a calling card as in the following example.
Û To omit the "1" prefix with a PBX system
2. In the Create New Calling Card dialog box, type a name for your calling card, such as "Direct Dial Through PBX." Click OK.
3. In the Change Calling Card dialog box, click Advanced.
4. In the Dialing Rules dialog box, complete the text boxes and then click OK.
Option | ||
Calls within the same area | ||
Long-distance calls | ||
International calls |
Using Microsoft File Transfer
Microsoft File Transfer allows you to send or receive a file while talking on the phone. When you send or receive a file, Microsoft File Transfer switches the phone line to data mode and temporarily suspends voice mode. Microsoft File Transfer switches the phone line back to voice mode when it has finished sending or receiving.
Microsoft File Transfer is automatically installed when you install a modem that supports its file transfer capabilities. For more information, see the online Help for Microsoft File Transfer.
Telephony Drivers from Other Vendors
There are several ways to add telephony drivers from other vendors, if necessary. Some telephony drivers work over the network and consist of software only. If this is the case, the software can be installed through the Add/Remove Programs option in Control Panel.
Hardware drivers can be installed through the Add New Hardware option in Control Panel, unless the hardware requires its own class installer. In this case, the hardware should come with a standard Setup program to install it.
You can also use the Telephony Control Panel, available in the Win32 Software Development Kit for Windows 95 and Windows NT, to install telephony drivers from other vendors.
If you previously installed the Telephony Control Panel on your Windows 3.1 system, and you upgrade to Windows 95, the Windows 95 Telephony Control Panel will be installed automatically.
Troubleshooting Communications Problems
This section describes how to solve problems with installing modems, making connections, and using applications to access the modem. Windows 95 provides a troubleshooting aid for modems in online Help. Try using online Help for troubleshooting before trying the steps included in this section. In addition, a general modem diagnostic tool is located in the Modems option in Control Panel. It provides information about each modem and COM port that have been configured on the computer.
Û To use the Modems Diagnostics Tool
2. In Diagnostics properties, click the Driver button to find out which communications driver is installed for Win16-based communications APIs. For these applications, the driver should be COMM.DRV. If a different driver is listed and you are having problems with using Win16-based applications, the driver is probably the cause.
3. In Diagnostics properties, click the More Info button to make sure Windows 95 can communicate with the modem. Clicking this button causes Windows 95 to send commands to and read responses from the modem, and then to display information about the modem and its COM port.
The Port Information box displays the following information:
u The UART type of the COM port, for example, 8250 or 16550A. Notice that 16550A UART ports can sustain faster connection speeds with fewer errors.
u The highest port speed supported by the modem. Never set the modems speed higher than the speed listed here.
The Modem Information box displays the modems responses to various AT commands that Windows 95 previously sent to it. Some modems return a response that indicates what make and model it is. This can help you select the correct modem if the Install New Modem wizard did not detect it correctly. Notice that many modems return "ERROR" for some AT commands. This means that the modem does not support that particular AT command.
The Record a Log File option in the Modems option also helps you identify modem problems by recording modem commands and responses in a MODEMLOG.TXT file.
Correcting Problems with Modem Installation
This section describes situations that can interfere with installation of a modem, and how to fix them.
The Install New Modem wizard detected the modem as a standard modem.
This does not indicate a problem. Rather, it means that Windows 95 was unable to detect the exact make and model of a modem. Most communications applications work correctly with the Standard Modem option, that is, connections can be made successfully using the modems factory default settings. However, advanced control of some features, such as speaker volume, error control (for example, V.42 protocol), and compression (for example, V.42bis protocol) will be disabled in the modems properties.
If you do not want to use the Standard Modem option, you can run the Install New Modem wizard to select a specific type of modem that is similar to the modem you are using. If you specify another, similarly named model from the same manufacturer for example, if you configure the modem as a Practical Peripherals PM9600HC when a Practical Peripherals PM9600FX modem is actually installed Windows 95 usually treats the models as being identical and the specified configuration will probably work well.
To determine whether other modem models are compatible with the one you are using, check the modem manual. Many modems are compatible with Hayes®, Microcom®, Rockwell, or U.S. Robotics models.
The Install New Modem wizard did not detect any new modems.
u Make sure no other programs are running that might be using the modem or its COM port.
u If the modem is external, check the connection between it and your computer, and reset it by turning it off and on again.
u If the modem is internal, make sure that its built-in COM port has been configured properly in Device Manager in the System option in Control Panel. If it does not appear, run the Add New Hardware wizard to allow Windows 95 to detect and configure it.
u Make sure the modems COM port is active and has a correct IRQ by checking its Resources configurations in Device Manager in the System option in Control Panel. Make sure the IRQ does not conflict with one in use by another device. For details, see Devices.
If the Install New Modem wizard still does not detect a modem, then there is probably a problem with the port, the cable, or the modem itself. Try the modem with an MS-DOS based communications program, or with another computer, if possible.
The Install New Modem wizard does not detect a PCMCIA modem.
If the Windows 95 PCMCIA drivers are loaded, then Windows 95 should automatically detect and configure a PCMCIA modem when it is installed. Use the PCMCIA option in Control Panel to check the configuration of a PCMCIA socket driver.
If the Windows 95 PCMCIA drivers are not being used, then the modem card must be configured as a COM port before the Install New Modem wizard can detect and configure it as a modem.
Û To detect and configure a PCMCIA modem when Windows 95 PCMCIA drivers are not used
2. Run the Add New Hardware wizard to detect and configure the card as a COM port.
3. Run the Install New Modem wizard to detect and configure the card as a modem.
For more information about PCMCIA devices, see Devices.
Correcting Connection Problems
This section describes basic steps for troubleshooting communications and explains specific communications errors or problems and how to correct them.
Modem will not dial or will not answer.
If your modem is not set up correctly, communications features might not function properly. The following procedures list steps in verifying the correct operation of your modem and the Windows 95 communications subsystem.
Because some communications programs designed for Windows 3.1 install incompatible driver files, which can cause COM ports and modems to stop working, start by verifying that the correct Windows 95 files are being loaded.
Û To verify that the required communications files are present
2. Confirm that the following lines are present in SYSTEM.INI:
[boot]
comm.drv=comm.drv
[386enh]
device=*vcd
3. To revert to the default communications drivers for Windows 95, delete communications port entries in Device Manager.
4. Run the Add New Hardware wizard in Control Panel to detect and install the Windows 95 drivers.
Windows 95 does not load the SERIAL.VXD driver in SYSTEM.INI. Rather, Windows 95 loads it on demand by using the Registry. Also, there is no corresponding file for the *vcd entry in SYSTEM.INI. This is an internal file built into VMM32.VXD.
Û To verify the modem configuration by using the Modems option in Control Panel
2. If your modem does not appear in the list of installed modems, click Add, and then select the appropriate modem.
3. If the manufacturer and model are not correct and are not available from the list, try the Hayes-compatible option or the Generic Modem driver option, set to the maximum speed supported by the modem. Click OK.
4. Try removing any other modem entries in the list to eliminate any conflicts.
Û To verify that the modem is enabled by using the System option in Control Panel
2. Click the option named The Device Is Present, Please Use It, if this is not already selected.
Û To verify that the port is correct by using the Modems option in Control Panel
2. In General properties for that modem, verify that the listed port is correct. If not, select the correct port. Click OK.
Û To determine if a serial ports I/O address and IRQ settings are properly defined by using the System option in Control Panel
2. Click the Properties button, and then click the Resources tab to display the current resource settings (IRQ, I/O) for that port. To find the correct settings, consult the modem manual.
3. In the Resources properties, check the Conflicting Devices List to see if the modem is using resources in conflict with other devices.
4. If the modem is in conflict with other devices, click the Change Setting button, and then click a Basic Configuration that does not cause resource conflicts.
Do not try to use a modem on COM3 if there is a serial mouse or other device on COM1. Usually, COM1 and COM3 ports use the same IRQ, meaning that they cannot be used simultaneously on most computers. The COM2 and COM4 ports have the same problem. If possible, change the COM3 or COM4 port to an IRQ setting that is not in conflict.
Also, some display adapters (especially S3, 8514A and ATI mach8) have an address conflict with COM4 ports. You can work around this by using another COM port or replacing your display adapter.
Û To check the port settings by using the Modems option in Control Panel
2. Click the Connection tab to check the current port settings, such as bits per second (speed), data bits, stop bits, and parity.
3. Click the Advanced button to check error control and flow control. If you are using Win16-based applications, turn off these advanced features.
4. Verify the UART type.
Data transmission problems can occur if a speed greater than 9600 is selected on a slower 80386-based computer not equipped with a 16550 UART, or when performing other tasks during a file download. If problems or errors occur during transmission, try lowering the speed. Attempting to use speed greater than 9600 on computers equipped with 8250 or 16450 UARTs will probably result in dropped characters.
Û To check the modem speed by using the Modems option in Control Panel
2. In General properties, check the speed to make sure it isnt set too high for either the modem or computer. Lower speeds might work, especially when using an older, slower computer.
3. Click the option named Only Connect At This Speed if it is not already selected.
To optimize communications performance, you can set the speed higher if your computer has an 80486 or a Pentium processor.
Û To disable hardware flow control if your modem cable doesnt support it
2. Click the Connection tab, and then click the Advanced button.
3. If a check appears in the Use Flow Control check box, click the box to clear it.
Û To remove VxDs from other vendors that might be interfering with modem operation
The initialization (dialing) string is improper for the modem.
If the modem will not pick up the line and dial, it might be due to an improper initialization string. Typically, the manufacturers recommended dial command string is loaded from the corresponding modem INF file; however, if your modem driver was not available and you selected a compatible modem, the dial command string might not work correctly. Try using the modem types, and retest the modem dialing the selected number.
The modem repeatedly drops the connection.
u Check the connection between the RJ-11 phone outlet and the modem. Verify that the connection is firmly plugged in and well connected.
u Try using a different phone line. If you have ruled out other factors, consistent modem errors might be due to problems in the telephone line used for communication.
u Disable call waiting, if it is in use. The call waiting feature can interfere with remote connections and file transfers. If you use this feature regularly, disable it only temporarily (during the time the modem is in use).
u Check communications with the host computer. The communications problems might be due to the host computer not connecting or repeatedly dropping the line.
u Try using a lower speed in the modem properties in the Modems option in Control Panel.
The COM ports remain in Device Manager after the modem is removed.
After installing an internal modem and assigning it to a COM port that does not physically exist on your computer, the port appears in the Device Manager. After removing this adapter, you might also need to manually remove the port in Device Manager as described in Devices.
You are unable to dial international calls.
Windows 95 allows you to set specific modem properties that assist you when making international calls over your modem. You set these properties in Dial-Up Networking, Dialing Properties, and in the modem properties.
Û To check location and calling card settings
2. In the My Locations properties, verify that your calling location and calling card settings are correct.
Û To disable dial-tone detection if your modem fails to detect a dial tone
Û To increase the time between dialing if connections are taking a long time
To manually control modem dialing.
Correcting Modem Access Problems with Applications
You cannot send or receive binary files by using HyperTerminal.
u If you are using the Ymodem-G file transfer protocol, ensure that your modem supports hardware error control. If it doesnt, try using Ymodem instead.
u If you are trying to use an alternative protocol (such as Kermit) and you encounter transmission errors, try Xmodem instead. Most communications packages, bulletin boards, and online services support Xmodem.
You cannot dial with Phone Dialer.
u For each access number you want to use for calling out, specify, at a minimum, the country code, area code, and telephone number.
u Verify basic modem and port configurations.
Win16-based applications cannot access the modem, but MS-DOS based or Windows 95-based applications can.
Make sure the communications driver for Windows 3.1-based applications is COMM.DRV in the SYSTEM.INI file. Some applications replace this driver for various reasons.
MS-DOS based applications cannot access the modem (especially PCMCIA modems), but all Windows-based applications can.
u If the MS-DOS based applications IRQ settings cannot be adjusted, adjust the IRQ settings for the modem COM port as described earlier in this section.
MS-DOS based and Windows 3.1-based applications cannot access the modem, but applications created for Windows 95 can.
Make sure that Microsoft Exchange Remote Mail, Microsoft Fax, and Dial-Up Networking are not waiting for incoming calls. If they are, older applications cannot access the modem.
Errors occur during MS-DOS based applications communications sessions, especially file transfers.
Increase the COMxBuffer setting in [386Enh] section of SYSTEM.INI. The default value is 128 bytes.