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July 7, 1997

Reader shares TAPI work-around for new modems

Telephony API, commonly known as TAPI, is the approved way for Windows 95 to mediate between communications software and communications hardware, such as modems. Although TAPI makes communicating more flexible than earlier versions of Windows did, it still has some wrinkles that need to be ironed out.

Reader Tom Berube, from Naperville, Ill., ran into one of these wrinkles recently. He was configuring users' communications software to dial various locations. Dialing these locations required some long numeric sequences that are now common with corporate calling cards.

To Berube's surprise, these lengthy sequences, which worked fine with older modems, would never go through on newer modems -- even modems from the same manufacturer.

Berube's research on and the subsequent work-around for this problem may be useful to anyone who needs to use a modem with Windows.

The actual problem, Berube found, is that Windows' TAPI dialer breaks up long dialing strings into chunks that are no longer than 40 characters. This behavior apparently is designed to accommodate some older modems that can't handle longer dialing strings all at once. The way some modems deal with the broken-up chunks of long strings, however, can cause some connections to fail entirely.

The first chunk emitted by the TAPI dialer begins with the familiar modem command ATDT. This code roughly translates as "ATtention and listen for Dial Tone." The TAPI dialer then emits the first chunk of the dialing string and terminates with a semicolon, which returns the modem to command mode.

The balance of the dialing string is sent by emitting another ATDT command followed by the remainder of the string.

Berube found that older modems, such as the Megahertz XJ1144, cope with the two broken-up chunks of data just fine. Newer modems, however, such as the Megahertz XJ4288 and Hayes Optima 28.8 EZ-Jack, wait for a dial tone upon receiving the second ATDT command.

Because the modem is in the middle of dialing a series of numbers, it never hears a dial tone and therefore never completes the dialing string.

The work-around is to configure your modem to "blind dial" by adding the command ATX1 to the Additional Commands section of your modem setup. You must also prefix all calls with a W command in the modem-location definition so your modem will wait for the initial dial tone.

Election update

In my May 12 column, I described how Microsoft billionaire Paul Allen had paid more than $4 million to Washington state to get a "quickie" seven-week special election to build a new stadium for his Seattle Seahawks football team. (See "Should Microsoft's millionaires face social obligations?".)

Allen subsequently spent more than $5 million on the campaign, making it the most expensive in the state's history. Citizens' groups opposed to the tax giveaway raised about $200,000. (I served as treasurer for the "No on 48" campaign.) Twenty-nine of the state's 39 counties voted no, but the measure narrowly passed, 51 percent to 49 percent, due to heavy Seattle-area turnout generated by incessant TV ads.

Brian Livingston is the co-author of Windows 95 Secrets Gold and four other Windows books (IDG Books). Send tips to or fax: (206) 282-1248.

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