telephones; telephone alarm monitoring systems, comprising telephones, receivers, transmitters, infrared detectors, sound detectors and parts therefor; receivers and transmitters; smoke detectors; infrared detectors; door sensors; sound sensors; panic/hold-up systems, comprising panic buttons, receivers, transmitters, semiconductors and parts therefor; medical alert systems, comprising panic buttons, receivers, transmitters, semiconductors and parts therefor; anti-theft devices, comprising ma...