From AMS Glossary
A remote indicator for wind speed and direction used in conjunction with a contact anemometer and a wind vane.
The indicator consists of a center light, connected to the contact anemometer, surrounded by eight equally spaced lights that are individually connected to a set of similarly spaced electrical contacts on the wind vane. Wind speed is determined by counting the number of flashes of the center wind vane during an interval of time. Direction, indicated by the position of the illuminated outer bulbs, is given to 16 points of the compass.