Testing Communications from MS-DOS

 Last reviewed: December 28, 1994
Article ID: Q84279
The information in this article applies to:
  • Microsoft Windows operating system versions 3.0, 3.0a, 3.1, 3.11

SUMMARY

When you troubleshoot communications problems in Windows, an MS-DOS-level communications program is often required to test the modem and ports outside of Windows.

If an MS-DOS-based application cannot be used, it is possible to test the modem connections by typing the following command at the MS-DOS command prompt 

   Echo ATDT > ComX
where X is the number of the serial port the modem is connected to or emulating.

The modem should respond with a dial-tone or just a communication signal.

MORE INFORMATION

The ATDT command is a signal to the modem that is interpreted as Attention Dial Tone. The first command, Attention, signals to the modem that it is about to receive information, and the Dial Tone command instructs the modem to enable a line to dial out.

NOTE: The modem may not always give a dial tone with this test procedure because a number does not follow the command; however, the modem should give some kind of signal that information was received.

KBCategory: kbother kbtshoot kbtlc
KBSubcategory: wincomm win31 win30
Additional reference words: 3.00 3.00a 3.10 3.11 COM1 COM2 COM3 COM4 AT DT
dos tshoot

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Last reviewed: December 28, 1994
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