Links to other Reference Manual pages:
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:
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:
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.
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.
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.
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:
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:
Step | Action | Notes |
---|---|---|
1 | Make sure your modem is configured properly: a. Check the settings in the software you are using. Use your telecom software to set your computer rate (serial port) to the highest speed supported by your computer -- at least 38,400. b. Use your software to turn ON hardware flow control (CTS & RTS [DTR]) and turn OFF software flow control (X-On/X-Off). c. Put your software in terminal mode if possible. d. From terminal mode, type AT&FØ [CR] (for PC). |
Your software manual provides more information on Steps a, b, and c. |
2 | Dial a number to find out if you can connect: From your software's terminal mode, type a phone number with which you have had line noise problems. ATDT number [CR] Do not use your software to dial the number. |
If you use your software to dial the number, it could change the configuration and cause problems. |
3 | If you still cannot connect, there may be too
much line noise to establish a high-speed
connection. Try to connect using V.32 instead: a. Type AT+MS=V32 [CR]. b. Repeat Step 2. |
AT+MS=V32 causes the modem to use the V.32 (9600 bps) protocol. |
4 | Disconnect other devices from the phone line: a. Unplug all other phone devices connected to the same phone line. Make sure there are no telephones, answering machines, other modems, etc. connected to any phone jacks on the same line. b. Repeat Step 2. c. If Step 4a solved the problem, try to determine which device is causing the problem. Then unplug that device and work through this checklist again. |
|
5 | Try using different phone wire from the wall to the modem. | Shorter wires work better. |
6 | Try using the modem at a different location. | |
7 | Consider the need for a second telephone line. | |
8 | Contact Technical Support. |
Slow Downloads
If you download files from a BBS or online service, you
should expect a theoretical CPS (character per second)
rate about 1/10th of your connection rate (i.e., 33,600
bps = 3360 cps) because it takes about 10 bits to
transmit each character.
There are many causes for slow transfer speeds. Your computer or software may not keep up. Slow disk drives on either end can slow it down. The remote server may be slow. The Internet between the remote server and the one you are dialing into may be slow. The server you have dialed into may be slow. The remote system may have many users on it, which slows it down. (You may find your best download speeds on many services are late at night when fewer users are on the service.) And some services are notorious for slow downloads in general. A download of 600 - 800 cps on a CompuServe 14,400 bps line is a normal occurrence.
Multitasking
Multitasking computers allow you to do many different
things while other operations take place in the
background. Although you don't see them in progress,
background operations can be complex and can sometimes
demand too much of your computer's attention to allow
high speed communications. High speed transmissions are
more reliable in a single-user situation with as few
applications as possible in use. Following are
platform-related specifics which can interfere with high
speed communications.
Displays
If you are downloading text that is displayed on your
screen as it is received, your computer's display may
have problems keeping up with the speed of the incoming
data. One way to get better performance is to change your
display to a lower number of colors, or monochrome, so it
is more efficient.
If you are having trouble making a high speed connection, you may wish to force your modem to a slower speed to see if it connects. Type AT+MS=V22B. This forces the modem to try to make a 2400 bps connection.
Line Noise Problems
Line noise is frequently a source of problems with high
speed modem connections. The following discussion
provides an overview of potential problems with
suggestions for troubleshooting.
Line Noise Problems on Fax Calls
Line noise is not a common cause of problems during fax
calls. If it is, one of the following may occur:
If you think you are having fax line noise problems, try
getting a clearer connection by redialing. If that
doesn't help, wait a while and try redialing again. This
should solve the problem. If necessary, and if your fax
software allows it, you can also try using your fax
software to set your fax transmission rate lower.
Line Noise Problems on Data Calls
With data calls, line noise can cause numerous problems.
In general, the faster you communicate, the better your
phone lines need to be. When you get up to 50,000 bps, it
is critical that you have clear lines from end to end.
Line noise can cause the following problems when trying
to make 9600 bps or higher data connections:
If you think you are having data line noise problems, try
redialing. When you redial, the phone company will
probably route your call through a different circuit,
which could result in a clearer connection. If that does
not help, wait a while and try redialing again. This
should solve the problem. If not, try using your software
to set your transmission rate lower. Refer to the Rate
Renegotiation discussion in the High Speed Communication
section for information on setting your transmission
rate.
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