Juniper Allegro CE Owner's Manual page 136

If the communication port you are using is not listed in the bottom
dialog box under Connect using, tap the Change button.
If the USB default is not selected, select the USB port from the drop-
down list. Tap the OK button.
To connect remove the Allegro from the USB/Power Dock then place
it back into the USB/Power Dock. This will automatically start the
connection process.
Page 4-76 Windows CE