Multi-Tech Systems MT2834ZDX 사용자 설명서

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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 StartProgramsAdministrative 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 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.