Multi-Tech Systems PN S000408C manual Modem Disconnects While Online

Chapter 7 – Troubleshooting

If you hear a dial tone, your modem might be installed behind a corporate 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. Check your 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 (note, however, that X3 is not allowed in some countries, such as France and Spain).

•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.

•If the modem reports NO CARRIER, the phone was answered at the other end, but no connection was made. You might have dialed a wrong number, and a person answered instead of a com- puter, or 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 modem is working. Also, try calling the number on your telephone. If you hear harsh sounds, then another modem is answering the call, and the modems might be having problems negotiating because of modem incompatibilities or line noise. Try connecting at a lower speed.

The Modem Disconnects While Online

•If you have Call Waiting on the same phone line as your modem, it can interrupt your connection when someone tries to call you. If you have Call Waiting, disable it before each call. In most telephone areas in North America, you can disable Call Waiting by preceding the telephone number with *70 (check with your local telephone company).

You can automatically disable Call Waiting by including the disabling code in the modem’s dial prefix (e.g., ATDT*70,—note the comma, which inserts a pause before the number is dialed). To change the dial prefix in Windows Terminal, select Settings Modem Commands. To change it in HyperTerminal, select Connect from the Call menu, click Dialing Properties, check This location has Call Waiting, and select the correct code for your phone service.

•If you have extension phones on the same line as your modem, you or someone else can interrupt the connection by picking up another phone. If this is a frequent problem, disconnect the extension phones before using the modem, or install another phone line especially for the modem.

•Check for loose connections between the modem and the computer, the telephone jack, and AC power.

•You might have had a poor connection because of line conditions or the problem might have originated on the other end of the line. Try again.

•If you were online, it might have hung up on you because of lack of activity on your part or because you exceeded your time limit for the day. Try again.

The Modem Cannot Connect When Answering

•The default DTR Control command (&D2) inhibits autoanswer. To enable autoanswer, change DTR Control to &D0, and make sure &Q0, &Q1, &Q5, or &Q6 is also set. For more information, see the &D command in the AT Command Reference Guide on the CD shipped with your modem. For information on changing the modem’s default configuration, see “Step 3: Install and Configure Your Software” in Chapter 2.

•Autoanswer might be disabled. Turn on autoanswer in your datacomm program or send the command ATS0=1 (ATS0=2 if you have Caller ID service) to your modem in terminal mode.

Multi-Tech Systems, Inc. MT5600BA-V92 User Guide 41