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Nor Storm Nor Virus Nor Even Shoddy Modems

Members of the ISP-Tech list discuss the most basic tech problem. When customers call your help desk saying they get no dial tone, how can you find out the cause of the problem, given so many possible culprits?

[March 21, 2001]

On the ISP-Tech list in March, MB inquired,

"In the last week or so I've had at least a dozen calls from people with the same problem: 'There is no dial tone.' The line is fine. Any idea what is going on?"

A number of users put forward their own guesses:

[PI offered] "Depending the country you're in, the phone and the modem may not be wired the same. In Switzerland, the phone uses wires 5 and 6 on an RJ45 while the modem uses 4 and 5. This is a real pain, and half the time we have to make a bridge on the wall plug or use a special cable for the modem. You might have the same connection problem."

[TB suggested] "Blame it on crappy Conexant modems. Just go into the DUN Properties for the dialer, select Configure, then click on Connection, then Advanced. In Extra Settings, put in AT+MS=V34 and be done with it."

[EC advised] "Try installing a known working modem into the PC. If you checked everything else, it's got to be a bad modem."

[JT recalled] "In every case I've ever run across where they got no dial tone, either the modem was broken or mis-installed, or they had their cabling wrong."

[LS noted] "If the problem has just started happening and is happening in bulk numbers, then something must have happened on a large scale to cause this problem. Usually, this is a result of an electrical storm causing damage to modems, a telco problem with local trunk lines, or a virus outbreak in or around the area. Several common worms like the Hybris worm affect the DUN package of the systems and pretty much wipe out your dialup .dll files."

Some were convinced that voice mail was the culprit:

[RR asked] "Did the local RBOC just start providing voicemail for the first time? When the dial tone is pulsing rather than monotonous, which is what happens when you have voicemail messages, most modems will return no dial tone. To quickly get around this, most modem control panels will have an ignore dial tone option, or will easily let you edit the modem string."

[BK added] "Or you could put in a few commas before the prefix, e.g. ,,5555555."

Others blamed forces of nature:

[MP advised] "Given the information that multiple users are having this same problem, lightning might be the cause."

[SY agreed] "After one storm, we had over twenty computers come through our shop for modem replacement. Plus, who knows how many more were also damaged but called someone else to have their modem replaced."

[HS added] "I usually check fried modems this way. First, Start|Run|dialer—have them type in your phone number—no dial tone or dial out failure. Then go to DUN|Properties|Configure|Options| and have them check 'Bring up terminal window after dialing.' After the dialing sequence, if there is any data going out, you will get a terminal window with a login prompt. No terminal window? No modem!"

—End