Assistive Listening Devices (ALDs)
1. Telephone Amplifiers.
2. Infrared Listening Systems for Television and Theater.
3. FM Listening Systems for lectures, conversation in noisy places, or at business meetings.
4. Devices to Warn of Fire.
5. Signalling Devices Such as Doorbells and Telephone Ringers.
6. Terminals to Communicate over Telephones.