MT3334ZDX/V Owner's Manual
20
The Modem Does Not Respond to Commands
• Make sure the modem is plugged in and turned on. (See “None of the
LEDs Light When the Modem Is On.”)
• Make sure you are issuing the modem commands from the data
communications software, either manually in terminal mode or
automatically once you have configured the software. (You cannot
send commands to the modem from the DOS prompt.)
• Make sure you are in terminal mode in your data communications
program, then type AT and press ENTER. If you get an
OK
response,
your connections are good and the problem likely is in your phonebook
entry or session settings.
• Try resetting your modem by turning it off and on. Make sure there is
a reset command (&F) in your initialization string, or your modem
may not initialize correctly.
• If you don’t get an
OK
, the problem may still be in the communications
software. Make sure you have done whatever is necessary in your
software to make a port connection. Not all communications programs
connect to the COM port automatically. Some connect when the
software loads and remain connected until the program terminates.
Others can disconnect without exiting the program. Many
communications software packages also allow multiple terminals to
be open, but only one can access the modem at a time. If your
package reports that it cannot make a connection, yet the modem’s

TR

indicator is on, click on the Window menu to see if more than one
terminal is open. The modem’s

TR

indicator shows that the software
has made a connection with the modem through the COM port.
• Your communications software settings may not match the physical
port the modem is connected to. The serial cable may be plugged into
the wrong connector—check your computer documentation to make
sure. Or you may have selected a COM port in your software other
than the one the modem is physically connected to—compare the
settings in your software to the physical connection.
• If the modem is on, the cable is plugged into the correct port, the
communications software is configured correctly, and you still don’t
get an
OK
, the fault may be in the serial cable. Make sure it is firmly
connected at both ends.
• Is this the first time you have used the cable? If so, it may not be
correct. Check the cable description on the packaging to make sure
the cable is the right one for your computer.