Multi-Tech Systems BL-Series User Manual
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Appendix A - Troubleshooting
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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 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 (make sure the Connect icon looks plugged in). If the terminal reports
that it cannot make a connection, yet the modem’s TR indicator is on, click on the Window menu
to see if more than one terminal is open. The modem’s TR indicator shows that the software has
made a connection with the modem through the COM port.
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Your communications software settings may not match the physical port the modem is connected
to. The serial 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 modem is physically connected to—compare the settings in your software to the
physical connection.
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If the modem 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 serial cable. Make sure
it is firmly connected at both ends.
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Is this the first time you have used the cable? If so, it may not be correct. Check the cable
description on the packaging to make sure the cable is the right one for your computer.
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Peripheral expansion cards, such as bus mouse and sound cards, may include a serial port pre-
configured 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 if you use Windows 3.1x, 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 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.
If you use Windows 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
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 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.
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The serial port may be defective. If you have another serial port, install the modem on it, change
the COM port setting in your software, and try again.
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The modem may be defective. If you have another Multi-Tech modem, try swapping modems. If
the problem goes away, the first modem is possibly defective. Call Tech Support for assistance
(see