Depending on what USB port you plug in device or adapters, your COM port will change. Here is how to find out what the setting is and to change if necessary. Devices often plugged in RS232 to USB communication port adapter, USB COM port, PCMCIA to USB adapter. Comport settings common COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8.

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Windows 95 COM port setting

1. Choose Start > Settings > Control Panel
   
2. In the Control Panel window, double-click the System icon and then click the Device Manager tab.
   
3. On the Device Manager card, determine the COM port settings for each COM port.
   
4. Double-click the Ports (COM & LPT) icon.
   

Windows XP COM port setting

1. Choose Start > Settings > Control Panel
   
2. Double-click Administrative Tools, double-click Computer Management, and then click Device Manager.
3. Double-click Ports (COM & LPT). Right-click the port for which you want to change settings, and then click Properties. On the Port Settings tab, make changes if necessary.

Windows Vista COM port setting

1. Choose Start > Control Panel > Device manager
2. Click continue if user permissions set up
3. Click plus sign next to Ports
4. Look for your device and view COM port used

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