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Solving Problems







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[Table of Contents]
[Introduction]
[Communication Standards]
[Using AT Commands and Result Codes]
[Dialing]
[Answering]
[High Speed Communication]
[Fax Features]
[If You Need Help]
[AT Commands]
[S Registers]
[Result Codes]
[Glossary]


This chapter discusses the following topics:

Check Your Equipment and Configuration
Problems with Plug and Play Installation
Problems Before Connecting
Problems When Trying to Connect
Problems While Connected
Problems with High Speed Connections


This chapter is designed to help you solve most communications problems you might encounter with your modem. To use the troubleshooting information, follow these steps:

  1. Try the suggestions in "Check Your Equipment and Configuration."
  2. Scan the text in the section that pertains to you your situation until you find a problem description similar to yours.
  3. Try using the possible solutions outlined in that section. It is most helpful to keep notes on what you try and what result you get.
  4. If the problem persists, scan the rest of this chapter. Certain solutions can be indicated by a number of different problems; and similarly, many problems have more than one solution. Try each solution that fits your situation before calling Technical Support.
  5. If you do not find a satisfactory resolution, you may need to contact Technical Support. Refer to your notes when you send email or call.

Check Your Equipment and Configuration
Before doing anything else, try completely disconnecting and then reconnecting the modem as described on the Quick Install Card. For your modem and many other electronic products, this solves common problems caused by incomplete connections.

If reinstalling your modem does not solve the problem, issue AT&F to return the modem to one of the factory default configurations (as explained in Chapter 2, Communication Standards). This may solve problems caused while trying to reconfigure the modem.

Compatibility With Other Modems
Your modem has been tested with most major brands of modems, and all of these modems work properly with the protocols your modem supports. If you cannot make a connection and you suspect the remote modem might be the source of the problem, consider the following:

Check that you have properly connected the incoming phone line into the socket on the modem.

Problems with Plug and Play Installation

Windows 95 Issues

Problem: After installing the Supra PC Card, when I access the modem with HyperTerminal or other communications software, I get the error message "COMx is already open or in use."

Solution: When using the OSR2 release of Windows 95, the operating system power management for PC Card modems should be disabled before attempting to install the modem for the first time. To check if OSR2 is the installed version of Windows 95, open Start, Click Settings, and then Control Panel. Double click on the System icon. If the version number of Windows 95 has the letter B as the last character, OSR2 is installed. Close the System file and double click on the Power icon. Select the tb PC-Card modems. The option “Turn off PC-Card modems when not in use” should NOT be checked. If it is checked, click on the check box to deselect this option. Then re-boot your computer. After the Supra PC Card has been installed, this option can be re-enabled. When using some applicataions (such as HyperTerminal) the card may take a couple of seconds to initialize, especilly if AT Commands are used instead of the buil-in dial feature, when this power management feature is enabled.

Problem: Does your computer have a Plug and Play BIOS?

Solution:

  1. In Windows 95, click Start, select Settings and choose Control Panel. Double click on the System icon and select Device Manager.
  2. Click System Devices.
    If your computer has a Plug and Play BIOS, it is listed here as a subcategory.


Problem: Software cannot access your modem on COM 5.

Solution: Software designed for Windows versions prior to Windows 95 may only support COM ports 1-4.

If there are four COM ports in the system or three COM ports and a video card based on the S3 chipset (which uses the 02E8, COM 4, address), then there is nothing you can do to avoid having your modem configure to COM 5, except disable a COM port so your modem can reconfigure to a lower COM port.


Problem: Your modem does not work on COM 1.

Solution: In this situation, COM 1 has been disabled but your modem still does not work or does not work properly. Even when you disable the port in the BIOS setup, Win95 may still assume it is a port which wants to use the default IRQ 4 and 3F8h settings and not allowing your modem to use those resources.

  1. In Windows 95, click Start, select Settings and choose Control Panel. Double click on the System icon and select Device Manager.

Check your changes in Device Manager. COM 1 now has a red X indicating Windows 95 does not reserve resources for the device, leaving IRQ 4 available for your modem.


Problems Before Connecting

Problem: Your software is not working properly.

Solution: Refer to your software manual for assistance.


Problem: What you type does not appear on the screen.

Solution: Enable command echo by issuing the ATE1 command. Alternately, you may be able to turn on Local Echo in your software.


Problem: Two letters appear on the screen for every one you type while in the command state.

Solution: Disable command echo by issuing the ATE command. You can also solve this problem by using your telecommunications software to change your computer setting to full duplex operation.


Problem: You type AT[CR] the modem does not acknowledge it with the OK Result Code.

Solutions: You are not in the command state. Enter the escape code (+++) to switch from online state to command state.
or
Your computer is set to a rate other than 300, 1200, 2400, 9600, 19,200, 38,400, 57,600, or 115,200. Use your software to change your computer rate to one of these rates.
or
Result Codes may be disabled. Issue the ATQ command.
orBR> Your computer's serial port is not working properly (external modems only). Contact your local computer dealer for assistance.


Problem: You type AT [CR] and the modem returns a Ø.

Solution:Your modem is set to use numeric Result Codes instead of verbose Result Codes. Use ATZ, or issue AT&F.

If these solutions do not solve your problem, contact Technical Support for assistance.


Problem: If your modem utilizes Flash ROM technology and it suddenly stops responding, or it doesn't respond when you turn it on, a Flash ROM error may have occurred.

Symptoms:If a PC card modem has a Flash ROM error, it will work well, then will suddenly stop responding to your software or commands and display a series of arrows and exclamation points on the screen. Your modem continues this display until you reset it.

Solution:Use another modem to download a flash utility from the one of these sources: Diamond's web site (www.Diamondmm.com), the Supra BBS, CompuServe (GO SUPRA), or our Internet FTP site (ftp://ftp.supra.com).


Problems When Trying to Connect

Refer to your Quick Install card and the Communication Standards section of this Reference Manual for information on modem connections.

Problem: If you get a NO DIAL TONE Result Code or you cannot get your modem to dial, one of the following may be the situation:

Solutions: You have too many devices on the line. Try unplugging other phone devices connected to your phone line. You might also try adding an X to the end of your initialization string.
or
Your Digital line or PBX does not support modems. Your PBX system must be equipped with standard analog lines for your modem.
or
If you have a voicemail system that gives you a stuttering dial tone to indicate new messages, then the modem should be set to ignore dial tone. Include several commas before the phone number to help the modem dial properly.
or
Your modem may have suffered damage from a recent power surge or an electrical storm. Contact Technical Support.


Problem: You are having trouble connecting and you suspect the remote modem might be causing the problem.

Solution: Refer to "Compatibility With Other Modems" in the opening section of this chapter.


Problem: You are having trouble making a Reliable connection.

Solutions:One of the following may be the solution:

Your modem is not set to make a Reliable connection. Issue AT&F (PCs) or issue \N2, \N3, \N4, or \N5. The Communication Standards section and the AT Commands list provide more information on these commands.
or
The remote modem does not support MNP or V.42. A Reliable connection is not possible in this case.
or
The remote modem supports MNP or V.42, but it is not in Reliable mode. Have the remote modem operator change to Reliable mode.
or
The remote modem supports MNP or V.42 and either gets confused by the length of time your modem takes to negotiate the connection or confuses negotiation characters with the remote computer's log-in sequence. In this case, issue AT\N (Normal) to disable error correction and data compression, and then dial again.
or
The telephone line quality is so poor and noisy that it interferes with the negotiation process. A variety of factors can cause line noise. Refer to the Line Noise discussion in the "Problems with High Speed Connections" section of this chapter to determine the source of the problem. You can also try to make a Normal connection.


Problem: Your modem is not recognizing busy signals, or your modem is interpreting other signals from the remote location as busy signals.

Solution: Be sure your modem is set to recognize dial tone and busy signal by adding an X2 to the end of your initialization string. Contact Technical Support for assistance.

If you cannot connect and these situations do not describe the problem, refer to the "Problems with High Speed Communications" discussion in this section.


Problems While Connected

Refer to your Getting Started manual, along with the Communication Standards chapter of this Reference Manual for information on modem connections.

Problem: You have connected to a remote modem but your computer has frozen up or all you see on your screen are garbage characters.

Solution: You have made a Direct connection, but your computer and modem are using different rates. Use your software to change the computer rate so it matches the connection rate given in the CONNECT Result Code.
or
Your computer and the remote modem are set to different data bits (word length), parity, and number of stop bits. The most common are 8 data bits (8-bit word length), no parity, and 1 stop bit (8, none, 1). Change these settings in your software.
or
Your computer and the remote modem are set to different terminal types. Change these settings in your software.
or
Your modem is not working properly. Contact your modem dealer for assistance.
or
Line noise could be causing the problem. Refer to the Line Noise Problems discussion in the Problems with High Speed Connections section later in this chapter.
or
You have selected hardware or software flow control on the modem (using AT&K3 or AT&K4), but not in your software. Both your hardware and software must be set to use the same type of flow control. If your software does not allow you turn flow control on and off, it either handles flow control automatically, or it does not support flow control. In this case, obtain software that supports flow control, or disable flow control by issuing the AT&KØ command.


Problem: You can connect but then can't communicate with the remote modem.
or
You can connect but then the modems disconnect for no apparent reason.
or
You can connect but then the modem speed drops unexpectedly.

Solution: Line noise could be causing the problem. Refer to the "Line Noise" sections later in this chapter.


Problem: Your transfer rate when downloading seems slow.

Solutions: If your software protocol (Xmodem, Kermit, etc.) shows many blocks being resent, you are probably losing data between the modem and computer - not the phone lines. Since the files you are transferring are probably pre-compressed, it will be best to set your computer rate close to the connection rate. We recommend 57,600 bps for most 33,600 bps connections. The section "Slow Downloads" later in this chapter provides more information.
or
If you are losing data when using Zmodem for file transfers, it is probably because your computer is busy doing other tasks, thus diverting attention from the download.

Use your software to reduce your computer rate (as described in the previous paragraph), use a different transfer protocol, or use software flow control.

The following steps explain how to use flow control:

  1. Use your software to turn OFF hardware (RTS/CTS) flow control. This automatically turns ON software (XON/XOFF) flow control, but you may need to use your software to manually turn ON software (XON/XOFF) flow control.


Problem: Your online communication is very slow, and you are using error correction (the TE or RE message may be displayed).

Solutions: You may be getting lots of transmission errors on a very noisy phone line (lots of static). In this case, the modem has to continually resend data, slowing your actual throughput. To solve this problem, try hanging up and reconnecting. See AT%Q2 in the AT Commands list for information on REJ and SREJ.


Problem: Your software locks up during a file transfer or large data transfer, and you are using hardware flow control (AT&K3).

Solutions: You may be trying to transfer binary data. Some data may include the special XON and XOFF characters which confuse the modem. Disable XON/XOFF flow control.
or
Flow control is turned off in your software. Use your software to turn flow control (or hardware handshaking) on.


Problem: You issue the escape code (+++) but the modem does not acknowledge it by sending the OK Result Code.

Solutions: You issued the code too quickly after the last characters were sent. Wait two seconds after sending any characters before issuing the escape code. Issue the escape code, and then wait two more seconds.
or
Your computer rate is different from the connection rate. Use your software to change your computer rate.
or
The escape code character has been changed in Register S2 from a plus sign (+) to something else. Change the escape code character back to a `+' or use the character in S2.


Problem: You cannot get your software to hang up.

Solution: Issue the escape code (+++) followed by the ATH command. Unplug the phone line from the wall to force the modem to hang up after a few seconds. (If this doesn't work, you can unplug the modem to make it hang up, but this is not recommended as an adequate long-term solution.)

To prevent future problems, after your software hangs up, check your software to see if it uses DTR or +++ to hang up. If your software uses DTR to hang up, add AT&D2 to the software's modem initialization string.
or
If your software uses +++ to hang up, increase the length of time between the +++ and the ATH in your software. Most software uses tildes (~) to lengthen time; if yours does, add two or three more tildes to increase the timing.

If these suggestions do not solve the problem, read your software manual to learn what your software needs to hang up properly.


Problem: You have changed your modem configuration and can't get your modem to work properly.

Solution: Try resetting it to the factory settings by issuing the commands AT&FØ (for PCs).

If these solutions do not solve your problem, contact Technical Support for assistance.


Problems With High Speed Connections

Your modem is designed to communicate at high speeds, but many factors contribute to the actual speeds you achieve during communication sessions. The information in this section helps you identify factors that may limit high speed communication and suggests possible solutions that will help you obtain the highest possible speeds for your modem.

Use the approach outlined below (Troubleshooting High Speed Data Connections) to identify the source of your problems. Then turn to one of the following sections:

Troubleshooting High Speed Data Connections
If you have trouble making a high speed data connection, first you need to determine the cause of the problem.

Identifying the Source of the Problem
Noise can be introduced at the remote site, by the phone lines, or at your local site. Before making any changes, try calling a few different remote modems to see if you have the same line noise problems with each attempt.

Use the following steps to identify the source of the problem:

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