5 Troubleshooting

To change a port address or IRQ in Windows 3.1x, 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.

Windows 9x and 2000: 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 communication port your modem 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 appears 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.

Windows NT 4.0: To look for address or IRQ conflicts, click Start, Programs, Administrative Tools (Common), and Windows NT Diagnostics. In the Windows NT Diagnostics dialog box, click the Resources tab to see which input/output ranges and interrupt requests are in use. 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 might be defective. If you have another serial port, install the modem on it, change the COM port setting in your software, and try again.

The modem may be defective. If you have another Multi-Tech modem, try swapping modems. If the problem goes away, the first modem may be defective. Call Technical Support for assistance (see Appendix D).

The Modem Dials But Cannot Connect

There can be several reasons the modem fails to make a connection. Possibilities include:

•lack of a physical connection to the telephone line.

•a wrong dial tone.

•a busy signal.

•a wrong number.

•no modem at the other end.

•a faulty modem, computer, or software at the other end.

•incompatibility between modems.

You can narrow the list of possibilities by using extended result codes. Extended result codes are enabled by default. If they have been disabled, include V1X4 in the modem’s initialization string, or in terminal mode enter ATV1X4 and press ENTER. When you dial again, the modem reports the call’s progress.

If the modem reports NO DIALTONE, check that the modem’s phone line cable is connected to both the modem’s LINE jack (not the PHONE jack) and the phone wall jack. If the cable looks secure, try replacing it. If that doesn’t work, the problem might be in your building’s phone installation. To test the building

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