Your Screen Displays Random or "Garbage"
Characters
Make sure that the modem is set to the same bit
rate, word length, parity, and number of Stop bits as the device to which
you are connecting.
If the settings are correct, the problem may be with the phone line.
Try the following measures:
Place the call again. The phone company routes even local calls differently
each time you call.
Call a different device to see if the problem persists. The problem
may be with the device you first tried to call.
If the modem is set to a fixed serial port rate (&B1) and your software
is fixed at 19.2K, 38.4K, 57.6K, or 115.2K bps, the reason may be one
of the following:
Your computer may not support the higher serial port rate. If this
is the case, fix your software rate at 9600 bps.
If you use memory-resident programs (TSRs-Terminate and Stay Resident
programs) or disk-caching programs, they may be interfering. Try disabling
them before you run your communications software.
Check that your software and the modem are set
for the same kind of flow control, either hardware or software. Some
communications programs also require that you disable the type you are
not using.
Many CRC Errors are Being Received
Send AT&F1 to enable hardware flow control and other optimised
settings.
Try a different file transfer protocol (use ZMODEM if it's available
to you).
If you use memory-resident programs (TSRs-Terminate and Stay Resident
programs) or disk-caching programs, they may be interfering. Try disabling
them before you run your communications software.
Mainframe Computer Keeps Dropping Your Connection
You must turn off the modem's result codes and character
echo (ATQ1E0). The modem at the mainframe also needs to be set to ATQ1E0.
Faxing Problems
Make sure the fax software is set to use Class 1 fax. Refer to your fax
software's manual.
If you use memory-resident programs (TSRs-Terminate and Stay Resident
programs) or disk-caching programs, they may be interfering. Try disabling
them before you run your communications software.
Both Devices Exchange Carrier Signals But Fail
to Establish a Communications Link
Make sure the modem is in the correct mode, fax
or data, depending on whether the connection is to be made with a facsimile
device or a data device.
Refer to the Modes of Operation section for information
on switching between Fax and Data modes.
Make sure the proper bit rate, word length, parity and number of
Stop bits have been selected.
Synchronous operations: review the instructions in the Dedicated/Lease
Line and Synchronous Applications section of the Content section. If
you've configured the modem correctly, the problem
may be with the synchronous adapter or with the system you're trying
to call.
Send ATI4 and check to see that your modem is at the correct Bn setting
to connect with either an HST modem (B1 setting) or “V.” modem
(B0 setting).
Make sure that your modem's connection rate setting,
&Nn, is correct for the call. If the connection rate is locked at
a speed (&N1-&N14) different from the calling modem's, the modem hangs up. The default setting of &N0, variable
link operations, allows the two modems to negotiate the highest possible
connection rate.
If your modem is Attempting to answer a V.32 call, you may need to
lengthen the extra V.32 answer tones. Refer to the Alphabetic Command
Summary appendix in this guide under S28.
If you are Attempting to make a connection using HST modulation, make
sure that the modem at the other end of the line is HST compatible,
V.32 terbo compatible at 14.4 Kbps, V.32 compatible at 9600 bps, V.22
bis compatible at 2400 bps, Bell 212A-compatible at 1200 bps, or Bell
103-compatible at 300 bps.
Errors During Software Download
Try performing the XMODEM file transfer, at a slower serial port rate.
If your computer doesn't have a 16550 UART, set your communications software
to use a slower serial port.