Multi Tech Equipment MTA128ST - Manual (Page 35)

Troubleshooting
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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 MTA1 28ST/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 MTA1 28ST/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 MTA1 28ST/NT may be defective. If you have another Multi-Tech MTA1 28ST/NT, try swapping
MTA1 28ST/NTs. If the problem goes away, the first MTA1 28ST/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.
• Awrong 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.
• If the MTA128ST/NT reports NO DIALTONE, check that the ISDN S/T cable is securely connected to
both the TA’s ISDN jack (not the PHONE jack) and the ISDN network terminator or wall jack. If the cable
looks secure, try replacing it. If that doesn’t work, the problem may be in your building’s telephone
installation. Make sure ISDN cables on all devices are wired straight-through (pin 1 to pin 1, pin 2 to pin 2,
etc.) and do not have reversed pairs. The cable must have at least the middle four pins (pins 3, 4, 5, and
6) connected. A reversed pair on the U (phone company) side is not important, but a reversed pair on the
S/T (your) side can create problems if you have more than one device, since multiple devices attached to
the S/T interface must all have the same polarity.
• If the MTA1 28ST/NT reports BUSY, the other number may be busy, in which case you should try again
later.
• If the MTA1 28ST/NT reports NO CARRIER, no connection was made. You might have dialed the correct
number but the other computer or software was turned off or faulty. Check the number and try again, or
try calling another system to make sure your TA is working. Also, check that you accurately configured
the TA with the correct switch type, TEIs, data protocols, and other parameters needed for a successful
call (see Chapter 3).
You can place data calls but not voice calls or vice versa
• You might not have ordered both voice and data service from your ISDN provider. Check your contract or
latest statement of service from your ISDN provider.
• Your ISDN provider may have programmed the switch incorrectly. Call the provider.