1. A method for optically communicating, from a user to a laser tracker, a command to control operation of the laser tracker with steps comprising: providing the laser tracker having a structure rotatable about a first axis and a second axis, a first motor that rotates the structure about the first axis, a second motor that rotates the structure about the second axis, a first angular encoder that measures a first angle of rotation about the first axis, a second angular encoder that measures a second angle of rotation about the second axis, a first light beam and a second light beam that are directed by the structure, a retroreflector target that reflects a portion of the first light beam as a third light and reflects a portion of the second light beam as a fourth light, a distance meter that receives a first portion of the third light and measures a distance from the laser tracker to the retroreflector based at least in part on a speed of the first light beam, a position detector that receives a second portion of the light and measures a position of the first light beam on the retroreflector, a photosensitive array that receives the fourth light, and a processor in communication with the first encoder, the second encoder, the first motor, the second motor, the distance meter, the position detector, and the photosensitive array, wherein the processor causes the first light beam to track the retroreflector based at least in part on the measured position of the first light beam on the retroreflector; providing a rule of correspondence between each of a plurality of commands and each of a plurality of temporal patterns of the fourth light; selecting by the user a first command from among the plurality of commands; projecting the second light beam from the laser tracker to the retroreflector; obtaining first sensed data by sensing the fourth light imaged onto the photosensitive array; generating by the user, between a first time and a second time, a first temporal pattern of the fourth light, the first temporal pattern of the fourth light including at least a decrease in optical power of the fourth light followed by an increase in the optical power of the fourth light, the first temporal pattern of the fourth light corresponding to the first command; determining by the processor the first command based at least in part on processing the first sensed data obtained between the first time and the second time according to the rule of correspondence; and executing the first command with the laser tracker.