Windows Mobile Device Center (WMDC) (aka ActiveSync) in Windows Vista supports synchronization between PDA and PC via Bluetooth connection. However, occasionally for odd reason such as your computer or Pocket PC is running on WidComm Bluetooth driver stack, the Bluetooth sync simply doesn’t work by simply selecting ‘Bluetooth’ in ‘Connection Settings’ in WMDC’s ‘Allow connection to one of the following’ option.

When a mobile device such as Pocket PC Phone detects and connects to a desktop or notebook computer via Bluetooth, it cannot determine if there’s any ActiveSync or WMDC service running in the background in the PC. To make thing worse, WMDC has dropped the ability to manually set the listening port for Bluetooth COM port. The older ActiveSync has this feature to support manual configuration of Bluetooth listening COM port.

The following registry hack provides the solution to unable to sync via Bluetooth with WMDC problem in Windows Vista. The registry hack has to be applied on desktop PC or laptop, and not the mobile device.

  1. Run Registry Editor (type regedit in Start Search and press Enter). Confirm any UAC dialog.
  2. Navigate to the following registry key:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows CE Services

  3. In the right pane, locate the value name SerialPort. Modify the value data from the default value of “Bluetooth or “Infrared” to COM4, where COM4 is the virtual COM port associated to your Bluetooth incoming COM port. If your PC uses different COM port number, then choose the right COM port as the value (e.g. COM5, COM6 etc).
  4. Exit Registry Editor.

Once the registry is set, WMDC will bind to a Bluetooth virtual COM port as incoming listening port instead of the generic Bluetooth name, which may not work for non-standard driver stack.