User`s guide

56K Professional Message Modem 33
PROBLEM
Your communications software
is reporting many cyclic
redundancy check (CRC)
errors and low characters per
second
(CPS).
DIAGNOSIS
You may have a bad
phone line.
Optimum flow control settings
may not be enabled on your
modem.
The serial port rate in your
communications software may
be set too high for
your area’s phone lines or your
modem’s UART.
The remote site you are
dialling into may have trouble
with the file transfer protocol.
There may be a Terminate
and Stay Resident (TSR)
program (such as a screen
saver or virus scanner)
running in the background,
disrupting data
communications.
You may be trying to download
a file to a compressed area of
your hard drive.
If your communications
program is DOS-based,
you’re running it under
Windows, and other software
is running, conflicts between
programs may be causing the
CRC errors.
POSSIBLE SOLUTION
Try placing the call again. The
phone company routes calls
differently each time.
Type this command in
terminal mode to load the
optimum hardware flow
control settings: AT&F1 and
press ENTER.
Lower the serial port rate in
your communications
software to 57,600 bps,
38,400 bps, or 19,200 bps.
Do not use 14,000, 28,800,
or 33,600. Note: The port
rate for a 56K modem cannot
be set lower than 57,600, if
you want to achieve a 56K
connection.
Try using a different file
transfer protocol. Do not use
Xmodem if other protocols
are available. Zmodem is the
preferred protocol.
Disable any Terminate and
Stay Resident (TSR)
programs running in the
background. If you have
software running as a TSR,
check the software’s manual
for information about
disabling its ability to operate
as a TSR.
Download to an
uncompressed area on your
hard drive.
Close every program but the
communications program.