Nikon Coolpix 300 - Manual (Page 94)

80 Connections : Making a Serial Port Connection
Note: While your COOLPIX 300 is being controlled by Nikon View, the
camera’s touch-panel display will not respond to the stylus and the record
and shutter-release buttons will be deactivated.
Note: Remove the serial cable from the camera and computer only after
both devices have been turned off. Unplug the cable by the connector, not
by pulling directly on the cable itself.