Multi-Tech Systems MULTIMODEM MT2834ZDX - Manual (Page 21)

Chapter 4 – Troubleshooting
Multi-Tech Systems, Inc. MT2834ZDX User's Guide 21
· Your communication program settings might not match the physical port the modem is connected to. The
serial cable might be plugged into the wrong connector—check your computer documentation to make sure.
Or you might have selected a COM port in the program other than the one the modem is physically
connected to—compare the settings in the program to the physical connection.
· If the modem is on, the cable is plugged into the correct port, the communication program is configured
correctly, and you still don’t get an OK, the fault might be in the serial cable. Make sure it is firmly connected
at both ends.
· Is this the first time you have used the cable? If so, it may not be wired correctly. Check the cable
description on the package to make sure the cable is the right one for your computer.
· Peripheral expansion cards, such as sound and game cards, can include a serial port preconfigured 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.
· If you use Windows 98, right-click on My Computer, select Properties from the menu, click on the Device
Manager tab, double-click on Ports, then double-click the communications port your modem is connected
to. In the port’s Properties dialog box, click 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 documentation for the device.
If you use Windows NT 4.0, select in turn Start, Programs, Administrative Tools (Common), and
Windows NT Diagnostics. In the Windows NT Diagnostics dialog box, click on the Resources tab to see
address and IRQ assignments.
· 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 might be defective. If you have another Multi-Tech modem, try swapping modems. If the
problem goes away, the first modem is possibly defective. Call Technical Support for assistance (see
Appendix C).
The Modem Dials But Cannot Connect
There can be several reasons the ZDX 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 will report the call’s progress.
· If the modem reports NO DIALTONE, check that the modem’s telephone line cable is connected to both the
modem’s LINE jack (not the PHONE jack) and the telephone wall jack. If the cable looks secure, try
replacing it. If that doesn’t work, the problem might be in your building’s telephone installation. To test the
building installation, plug a telephone into your modem’s telephone wall jack and listen for a dial tone. If you
hear a dial tone, your modem might be installed behind a company phone system (PBX) with an internal dial
tone that sounds different from the normal dial tone. In that case, the modem might not recognize the dial
tone and might treat it as an error. Make sure your modem’s square wave ring detection is turned on
(&RD1). Check the PBX manual to see if you can change the internal dial tone; if you can’t, change your
modem’s initialization string to replace X4 with X3, which will cause the modem to ignore dial tones.
· If the modem reports BUSY, the other number might be busy, in which case you should try again later, or it
might indicate that you have failed to add a 9, prefix to the phone number if you must dial 9 for an outside
line. If you must dial 9 to get an outside line, the easiest way to dial it automatically is to include it in the
modem’s dial prefix, e.g., ATDT9,. Note the comma, which inserts a pause before the number is dialed. By
inserting 9, into the dial prefix, you do not have to include it in each directory entry. To change the dial prefix
in Windows 95 HyperTerminal, select Connect from the Call menu, click Dialing Properties, and type 9 in
the local and long distance boxes in How I dial from this location.
· If the modem reports NO ANSWER, the other system has failed to go off-hook, or you might have dialed a
wrong number. Check the number.