FM systems use radio signals to transmit amplified sounds. They are often used in classrooms, where the instructor wears a small microphone connected to a transmitter and the student wears the receiver, which is tuned to a specific frequency, or channel. The receivers come in various forms. A neckloop, for example. Or something called a silhouette inductor, installed behind a hearing aid or cochlear implant.
FM systems can transmit signals up to 300 feet and are able to be used in many public places.
Infrared systems work the same as FM systems, except that they use infrared light to transmit sound. Unlike induction loop or FM systems, the infrared signal cannot pass through walls, making it particularly useful in courtrooms, where confidential information is often discussed, and in buildings where competing signals can be a problem, such as classrooms or movie theaters.
Personal amplifiers are good alternatives for when watching TV, being outdoors, or traveling in a car. About the size of a cell phone, these devices increase sound levels and reduce while reducing background noise for a listener. Some have directional microphones that can be angled toward a speaker or other source of sound. As with other ALDs, the amplified sound can be picked up by a receiver that the listener is wearing, either as a headset or as earbuds.
For many years, people with hearing loss have used text telephones, TTY or TDD systems machines, to communicate by phone. Machines equipped with typewriter keyboards that displays typed conversations onto a readout panel or printed on paper. The advent of digital devices like cell phones, tablets and laptops have rendered TTY machines practically obsolete.
That said, for people with mild to moderate hearing loss who prefer to carry on a spoken conversation, there is technology that provides a transcript of the other person’s words on a readout panel or computer screen as back-up.
Alerting or alarm devices use sound, light, vibrations, or a combination of these techniques to signal people with hearing loss. Clocks and wake-up alarm systems allow a person to choose to wake up to flashing lights, horns, or a gentle shaking.
Visual alert signalers monitor a variety of household devices and other sounds, such as doorbells and telephones. In addition, remote receivers placed around the house can alert a person from any room. Portable vibrating pagers can let parents and caretakers know when a baby is crying. Some baby monitoring devices even analyze a baby’s cry and light up a picture to indicate if the baby sounds hungry, bored, or sleepy.