Abstract: An apparatus includes a controller for controlling operation of an appliance, an indicator light coupled to the controller to provide a visible indication of an operator selection in response to the controller energizing the indicator light, and a driver coupled to the controller and the indicator light so that the controller may communicate data through the indicator light by controlling the driver. The indicator light may be a light emitting diode or a segment of an alphanumeric display of an appliance control panel. A detector LED may also be coupled to the controller so the controller may receive data from an external device that communicates by flashing light on the detector LED. A terminal for communicating with the appliance may include a detector LED and a conductor that couples the detector LED to a diagnostic tool. The detector LED may receive data from an optical transmitter of the appliance control panel.

Abstract: In analyzing radiation from a sample, single-quanta counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of fluorescent radiation. Preferred detection techniques include methods in which (i) fluorescence-stimulating radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the fluorescent radiation which is intensity-modulated with the preselected code, and (iii) wherein modulation with a preselected code is applied to a sample to influence a property which functionally affects emitted fluorescent radiation. For registration of the signals from a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.