New telephone equipment for the hard of hearing

Dec. 12, 1967 - NEW TELEPHONE SIGNAL FOR THE HARD OF HEARING. Western Electric's Maury McElroy displays a new product of his company for Bell System customers who have difficulty hearing telephone rings. The Tone Ringer was developed by Bell Laboratories and now is in initial production at Western Electric's Indianapolis Works. A transistorised device, it does electronically and acoustically what a bell cannot do. The ringer's fundamental tone is 750 hertz (or cycles per second) and its first harmonic is 1, 500 hertz. Tests show these frequencies get through to persons with defective hearing, but are not irritating to those with normal hearing. Other harmonics that would be unpleasant (2, 250 and 3, 000 hertz) are attenuated by the small plastic cylinder projecting above the larger cylinder on the left. The Tone Ringer can be mounted on a wall in a central location of a home, inside an ivory- or gold-coloured cover (right). There is a control to raise or lower volume

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