Modem Help Guide to Diagnose Modem Problems
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A.Introduction (Please Read First)
B.Common Modem Errors
C.Possible Quick Fix- IGNORE DTR -for Windows 3.x and Macintosh
D.Windows 95 Dialer and Dial-Up Networking Modem Help
E.Changing Your Modem Strings (Default Modem commands)
F.Verify your modem is not an RPI SW Error Correcting Modem
G.Verify your Modem has the latest Firmware Updates
H.UART Chip Information and how they effect External Modems

A. Introduction (Please Read First)

This guide is designed to help you track down possible problems with your modem. A modem is the central and most important part of any dial connection. Modems come in a wide variety of performance levels and price ranges. A good hardware error correcting modem with updated firmware will usually give a solid and stable connection. The other two important components of your dial connection are your software/operating system and phone line. The Software/operating system is another key component because it controls your modem. Make sure you have the help document for troubleshooting your dial software. There is an available guide for troubleshooting phone lines as well.

B. Common Modem Errors

1.Modem does not Initialize (does not give an OK when commands are sent)
2.Modem gives an endless or long handshake when connecting
3.Dropped Connections and overall bad connection performance
4.Getting the error message "Your Modem or TCPIP configuration may be in Error the first and second configuration servers are unavailable"

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If you are using Windows 3.x or a Macintosh machine you can try enabling IGNORE DTR or appending the modem command &D0. This can be used anytime a connection fails after an attempted handshake. With Ignore DTR you may have a problem getting your modem to disconnect. If so, try adding S10=200 or S25=200 to the end of the second command string without enabling Ignore DTR. To add this use Create in the Modem Settings Page. One of these S commands should be recognized by the modem and one will not. If this fails go to the next sections.

D. Windows 95 Dialer and Dial-Up Networking Modem Help

Modems must be installed in Windows 95 inside the Modems Control Panel. Dial-Up Networking (DUN) is the built in Win 95 dialer and it uses this modem installation. Our Win 95/NT dialer is an interface over DUN so it uses this modem installation as well. Note that Windows 3.x (or 16-bit) dialers still work in Windows 95, but they initialize the modem apart from Win 95. If using our Win 3.x dialer in Win 95 follow the fixes for Win 3.x. It is not usually necessary to modify modem commands in Win 95 (to append to your Win 95 modem string go to Control Panel, Modems, highlight your modem, click Properties, Connection tab and click Advanced. Add commands to Extra settings without adding an AT). If you are having connection problems (i.e. disconnecting) try lowering your modem settings as follows:

Click My Computer, then DUN. Right click the IBM Global Network Icon and choose Properties. Choose Configure and drop the Maximum Speed to 19,200 and click the Connection Tab and choose Port Settings. Uncheck Use FIFO Buffers after lowering the Receive and Transmit Buffers. Retry your connection. If you can connect or your modem no longer drops try slowly increasing these settings to find your maximum performance.

Click the Advanced from the connection tab and verify Use error control, Compress data, Use flow control and Hardware (RTS/CTS) are checked. Download the latest modem drivers from your manufacturer. If these procedures fail see the section on Software Error Correction, Firmware updates, and UART information.

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Before trying these modem strings be sure and try some of the modems already listed in your software i.e. Hayes Compatible, Default, Other, and Hayes modems etc. Also make sure you have the latest modem list in your Software (see related documents). Also verify your modem cables are secure and the com port is correct. To change the modem commands in the software itself simply go to your Modem Settings page. You will either see fields to type in new modem commands or you will see your modem name. Use the Create button in the modem settings page to add these strings.

These strings are also listed in the MODEM.LST file on the FTP site and should be in the latest software. So if you have already tried these default modem types skip to the Secondary Default strings below.

MODEM TYPE 1ST (Initialize) 2ND COMMAND MODEM STRING (Originate)

Default AT&F AT&D2&C1X4V1Q0S7=70
Default Type 10 AT&F AT&D2&C1X4V1Q0S7=70W2\N3&K3
Default Type 20 AT&F AT&D2&C1X4V1Q0S7=70\N3&K3
Default Type 30 AT&F AT&D2&C1X4V1Q0S7=70\G0\N3\Q3
Default Type 35 AT&F AT&D2&C1X4V1Q0S7=70\N3\Q3\J0
Default Type 50 AT&F AT&D2&C1X4V1Q0S7=70\N3\Q3
Default Type 60 AT&F AT&D2&C1X4V1Q0S7=70W2\G0&Q5&K3\J0
Default Type 64 AT&F AT&D2&C1X4V1Q0S7=70W2&Q5&K3\J0
Default Type 66 AT&F AT&D2&C1X4V1Q0S7=70&Q5&K3\J0
Default Type 70 AT&F AT&D2&C1X4V1Q0S7=70&Q5&K3
Default Type 80 AT&F AT&D2&C1X4V1Q0S7=70&M4&H1&B1

Note: You can also try changing the &D2 to &D0 in the above commands. Especially if using WIN 3.x or Macintosh Systems.

The following are other strings that can be used. These strings only use one command modem string instead of two so leave the 2nd field blank, add the same string again or add AT. These are not in the modem.lst file. Secondary Default strings

DEFAULT 1 AT&F
DEFAULT 2 AT&F1
DEFAULT 3 AT&F2
DEFAULT 4 AT&F0

F. Verify your modem is not an RPI SW Error Correcting Modem

If your modem has an RPI chipset and it is a Class 1 modem, it does not support hardware error correction. Error Correction is the feature in high speed modems that allow it to compensate for changes in line conditions. The modem will actually decrease and increase its connection speed depending on the current line conditions. Hardware error correction is when the modem itself regulates the error correction. Software error correction is where the modem has to rely on the computer processor to perform the error correction. Software error correction can cause long delays which usually ends in a disconnection. Since our service requires hardware error correction these modems are unreliable at the very best. The best way to find out if you have a software error correcting modem is to call your modem manufacturer and ask them if your modem model is software error correcting. If you verify your modem is hardware error correcting you should check for the latest version of error correction.

Most Hardware Error correcting modems offer Firmware Updates meaning the modem can be upgraded without having to purchase a new modem. There are two different kinds of Firmware upgrades:

1.EPROM (Erasable Programmable Read Only Memory) - An actual chip is sent from the modem manufacturer to replace the existing chip. This is usually done for a small fee unless there is a known bug with your firmware revision (which is the case most of the time). Make sure you tell them you are having problems.

2.FLASH Upgrades - These are basically software upgrades that are burned into the modem. They are usually free and offered off the Modem Manufacturer's Home Page or BBS.

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Some connection errors are caused by a downlevel version of an interface chip called the Universal Asynchronous Receiver Transmitter (UART). It can be found on your computer com port or on your internal modem. The latest level of this chip provides the role of a 'traffic cop' and buffers the incoming data from the modem for the PC to process. Versions of UARTs include: 8250, 16450, 16550, and 16550a. You should have a 16550a UART for 14.4 modems and higher. To update your UART you may purchase an internal modem with a built in UART or obtain an I/O serial card with a 16550a UART for external modems. Otherwise lower the modem speed to 9600.

Do the following to determine what UART level you are using:

1.In Windows 95 go to the Modems icon in Control Panel. Click the tab Diagnostics and highlight your modem name. Click the button More Info... (while not dialed in) and the UART type will be displayed.

2.In Windows 3.x exit Windows and go into a DOS mode (it is important to run this in Dos and not a Dos Window). Type the command MSD at the Dos prompt, choose the option Com Ports and read the UART chip type at the bottom of the Window.

3.In OS/2 Warp type MODE COMx (where x is the com port) in an OS/2 Window. If the BUFFER field is AUTO you have a 16550 UART.