3Com OfficeConnect Getting Started Manual page 14

Double characters are appearing on your monitor
After you dial, the Business Modem reports NO CARRIER and then hangs up
Hear ringing but the Business Modem won't answer
The Business Modem acts as though a data link has been established, but no call was
received,
The Business Modem behaves as if <Enter> were pressed when you don't press any keys
This is a signal that both the Business Modem's local echo and your
software's local echo are on.
Type the command to turn off your online echo (ATF1) or turn your
communications software's local echo off (refer to your software's
documentation).
Try increasing S7 and decreasing S9 to allow more time for the
connection.
Try calling a different device. If you are trying to connect to an older
modem at 2400 bps or less, it may not support error control. Try
sending AT&M0, and then try the call again. Reset the Business
Modem (send ATZ) after you finish the call.
Look at the TR LED to make sure that your terminal or computer is
sending a DTR signal via the EIA-232 interface.
Send ATI4 to the Business Modem and check that S0 is set to a value
higher than 0.
Set &F1 and S0=1, then try again.
Carrier Detect (CD) may be overridden (with &C0), but your system may
require that the override be turned OFF (with &C1). Review your
communications software manual to see what CD operations are
required.
Your software may be misreading signals from the Business Modem when
the Business Modem sends a Carriage Return and a Line Feed before and
after the RING and CONNECT messages. Sending the Quiet mode
command, ATQ1, should solve the problem.
Problems That Occur Before Connecting 3-3