A voice activated wireless phone headset whereby power control, timer and noise level recognition circuits sample ambient noisevoice levels and at predetermined levels provide an \u201coff-hook\u201d telephone condition. The front tabletop is supported by a carriage which allows the position of the front tabletop to be adjusted fore and aft, while maintaining it in a horizontal plane. The scanner also has an optical member provided on the rotatable member that allows the scanning light beam to pass therethrough to be incident upon the incident surface of the photo-detector, and a device for adjusting rotational position of said rotatable member about said rotational axis.