Microsoft KB Archive/112841

= COM Port Settings in Control Panel vs. Command Prompt =

Article ID: 112841

Article Last Modified on 2/20/2007

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APPLIES TO


 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Workstation 3.1
 * Microsoft Windows NT Advanced Server 3.1
 * Microsoft Windows NT Workstation 3.5
 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 3.5
 * Microsoft Windows NT Server 3.51
 * Microsoft Windows NT Server 4.0 Standard Edition

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This article was previously published under Q112841





SUMMARY
The COM port settings in the Ports option of Control Panel have no effect on COM port settings used in a command prompt window.



MORE INFORMATION
MODE.COM queries the port directly. Default settings are the following:

  Status for Device COM1: ---   Baud:            1200 Parity:         Even Data Bits:      7 Stop Bits:      1 Timeout:        OFF XON/XOFF:       OFF CTS handshaking: OFF DSR handshaking: OFF DSR sensitivity: OFF DTR circuit:    ON    RTS circuit:     ON

Applications reset the mode of the COM port(s). If, for example, you start Terminal and reset COM1 to 14400 baud, 7 data bits, odd parity, then exit Terminal, the new settings remain in effect until the computer is shut down. Upon rebooting, the default settings are once again in effect. The Control Panel settings, on the other hand, affect the registry. An application that is appropriately written can query the registry for these values and use the Control Panel settings. The default settings in the Ports option of Control Panel are:

  Settings for COM1: ---  Baud Rate:     9600 Data Bits:    8 Parity:       None Stop Bits:    1 Flow Control: None

Additional query words: prodnt 3.1 3.5 4.0

Keywords: kbhardware KB112841

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