COM Port Settings in Control Panel vs. Command Prompt (112841)


The information in this article applies to:

  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional
  • Microsoft Windows NT Server 3.1
  • Microsoft Windows NT Workstation 3.1
  • Microsoft Windows NT Advanced Server
  • Microsoft Windows NT Workstation 3.5
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Workstation 4.0
  • Microsoft Windows NT Server 3.5
  • Microsoft Windows NT Server 3.51
  • Microsoft Windows NT Server 4.0
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
Modification Type:MajorLast Reviewed:5/6/2003
Keywords:kbHardware KB112841
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