How do deaf people answer a doorbell? Hear a smoke alarm?
Deaf people don’t worry about missing the doorbell: flashing lights, rather than chimes, alert them to visitors. Similarly, smoke detectors, phones and alarm clocks can all be converted to feature deaf-friendly flashing lights or very loud alarms, and even vibrating mechanisms that shake the bed or buzz in the occupant’s pocket. Entire systems can be designed that combine all these alerts into a small, portable vibrating beeper. How do deaf people use the phone? Deaf or hearing-impaired people can use a TTY or TTD (telephone typewriter or telecommunications device for the deaf both can be used to describe the same devices) at home or on the road. The traditional TTY or TTD looks a bit like an electric typewriter or word processor with a small text display screen. Some have printer functions and answering machines. The TTY can only receive information from another TTY, since each part of the call is converted to beeps and relayed over phone lines like a fax. To facilitate communications
