The Modem Does Not Respond To Commands - Multitech MultiModem MT5600ZDX User Manual

5 Troubleshooting

The Modem Does Not Respond to Commands

Make sure the modem is plugged in and turned on. (See "None of the Indicators
Light.")
Make sure you are issuing the modem commands from the data communications
program, either manually in terminal mode or automatically by configuring 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 E . If you get an OK response from your modem, your
NTER
connections are good and the problem likely is in the connection setup in your
communications program.
Try resetting your modem by turning it off and on. If you are using DOS or
Windows 3.1 communications program, make sure the initialization string
includes &F as the first command, to cancel any "leftover' command that could
affect the modem's operation.
If you don't get an OK, the problem may still be in the communications program.
Make sure you have done whatever is necessary in your software to make a port
connection. Not all communication 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. The modem's TR indicator lights to show that the software has taken
control of the modem through the COM port.
Your communications program settings may not match the physical port the
modem is connected to. The serial cable might be plugged into the wrong
connector—check your computer documentation to make sure. Or you might
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 program is configured correctly, and you still don't get an OK,
the fault might 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 wired correctly.
Check the cable description on the packaging to make sure the cable is the right
one for your computer.
Peripheral expansion cards, such as sound and game cards, might include a
serial port preconfigured as COM1 or COM2. The extra serial port, or the card
itself, may use the same COM port, memory address, or interrupt request (IRQ)
as your communication port. Be sure to disable any unused ports.
Windows 3.1x: To look for address or IRQ conflicts, in Program Manager select
File | Run, type MSD, and press E . Then select Mouse, COM Ports, and
NTER
IRQ Status, and note the addresses and IRQs that are in use. If you find an IRQ
conflict, note which IRQs are not being used, then change one of the conflicting
devices to use one of the unused IRQs. If you find an address conflict, change the
address of one of the conflicting devices.
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