Multi-Tech Systems MTA128ST-USB - Manual (Page 63)

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Chapter 5 - Troubleshooting
MTA128ST-USB
The MTA128ST-USB does not respond to commands
• Make sure the MTA128ST-USB is plugged in and turned on. (See None of the LEDs
Light When the MTA128ST-USB Is On.)
• Try resetting your MTA128ST-USB by turning it off and on.
• Make sure you are issuing the MTA128ST-USB commands from the data
communications software, either automatically, or manually in terminal mode. (You
cannot send commands to the MTA128ST-USB 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 may be in your phonebook entry or session settings.
• 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 automatically to the COM
port. Some connect when the software loads and remain connected until the program
ends. Others, like MultiExpress Terminal, can disconnect without ending the program
(make sure the Connect icon is plugged in). MultiExpress Terminal also allows
multiple terminals to be open, but only one can access the MTA128ST-USB at a
time. If MultiExpress Terminal reports that it cannot make a connection, yet the
MTA128ST-USB’s TR indicator is on, click on the Window menu to see if more than
one terminal is open. The MTA128ST-USB’s TR indicator shows that the software
has made a connection with the unit through the COM port.
• Your communications software settings may not match the physical port the
MTA128ST-USB is connected to. The USB 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 MTA128ST-USB is
physically connected to—compare the settings in your software to the physical
connection.
• If the MTA128ST-USB 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 USB cable. Make sure it is firmly connected at both ends.
• Is this the first time you have used the cable? If so, check the cable description on
the packaging to make sure the cable is correct for your computer.
• Peripheral expansion cards, such as bus mouse and sound cards, may include a
USB port preconfigured as COM1 or COM2. The extra USB port, or the card itself,
may use the same COM port, memory address, or interrupt request (IRQ) as your
communications port. Be sure to disable any unused ports.
If you use Windows 98/95, right-click on My Computer, select Properties from the
menu, click on the Device Manager tab, double-click on Ports, then double-click on
the Communications Port your MTA128ST-USB is connected to. In the port’s
Properties sheet, click on the Resources tab to see the port’s Input/Output range and
Interrupt Request. If another device is using the same address range or IRQ, it will
appear in the Conflicting Device List. Uncheck Use Automatic Settings to change the
port’s settings so they do not conflict with the other device, or select the port the
conflicting device is on and change it instead. If you need to open your computer to
change switches or jumpers on the conflicting device, refer to the device’s
documentation.
• The USB port may be defective. If you have another USB port, install the
MTA128ST-USB on it, change the COM port setting in your software, and try again.