Multi-Tech Systems MTA128NT - Manual (Page 37)

Troubleshooting
MTA128ST/NT 37
• 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 serial port preconfig-
ured 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 communications port. Be sure to disable any unused ports.
To look for address or IRQ conflicts, select File, Run in Program Manager, type MSD, and press ENTER.
Then select Mouse, COM Ports, and 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.
To change a port address or IRQ, double-click the Control Panel icon, then the Ports icon. Click on the
port you want to change, click Settings, click Advanced, and select the new port address and/or interrupt.
If you wish to use COM3 or COM4, note that COM3 shares an IRQ with COM1, as does COM4 with
COM2, so you should change their IRQs to unused ones, if possible.
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/NT 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 serial port may be defective. If you have another serial port, install the MTA128ST/NT on it, change
the COM port setting in your software, and try again.
• If using serial rates above 115,200 baud, make sure the serial port can handle higher rates. Most
standard serial ports have a maximum serial rate of 115,200. To handle serial rates of 230,400 baud and
460,800 baud, you need a high-speed serial port Even though some terminal emulation programs allow
you to select higher rates, the serial ports cannot always handle those rates.
• The MTA128ST/NT may be defective. If you have another Multi-Tech MTA128ST/NT, try swapping
MTA128ST/NTs. If the problem goes away, the first MTA128ST/NT is possibly defective. Call Tech
Support for assistance (see Chapter 7).
The MTA128ST/NT dials but cannot make a connection
There can be several reasons the MTA128ST/NT fails to make a connection. Possibilities include
• Lack of a proper physical connection to the communication line.
• A busy signal.
• A wrong number.
• No terminal adapter at the other end.
• A faulty communications device, computer, or software at the other end.
• Incompatibility between communications devices.
• An improperly configured MTA128ST/NT.
Narrow the list of possibilities by using extended result codes. To enable them, enter ATV1X2 and press
ENTER while in terminal mode or include V1X2 in the MTA128ST/NT’s initialization string (V1X2 is enabled
by default). When you dial again, the MTA128ST/NT reports the call’s progress.