Abstract: A portable telephone answering device which fits over the cradle of a telephone handset and receives the handset with a speaker adjacent the handset microphone and a microphone adjacent the handset speaker. An outgoing message can be recorded on one track of a multi-channel loop of tape. When ringing is detected, the telephone plungers are released and the outgoing message played. Next the unit records an incoming message on another track. A metallic splice on the loop serves as a reference. The number of channels on which an incoming message has been recorded are counted and the count incremented only if audio signals are detected indicating a message was left.

Abstract: A photoelectric beam system for the detection of the arrival of an object at a discrete station wherein artificial light, natural light, or no light may be present. A signal generator turns on and off a signal light at a selected frequency. When the object in question arrives on station, ambient light is blocked by the object, and the light from the signal light is reflected onto a photoelectric sensor which has a delayed electrical output but is of the frequency of the signal light. Outputs from both the signal source and the photoelectric sensor are fed to inputs of an exclusively OR detector which provides as an output the difference between them. The difference signal is a small width pulse occurring at the frequency of the signal source. By filter means, this signal is distinguished from those responsive to sunlight, darkness, or 120 Hz artificial light. In this fashion, the presence of an object is positively established.