Table A2
Summary of Assistive Listening Devices
| System | Advantages | Disadvantages | Typical Applications |
Induction Loop Transmitter. Transducer wired to induction loop around listening area. Receiver. Self-contained induction receiver or personal hearing aid with telecoil. | Cost-Effective Low Maintenance Easy to use Unobtrusive May be possible to integrate into existing public address system. Some hearing aids can function as receivers. | Signal spills over to adjacent rooms. Susceptible to electrical interference. Limited portability Inconsistent signal strength. Head position affects signal strength. Lack of standards for induction coil performance. | Meeting areas Theaters Churches and Temples Conference rooms Classrooms TV viewing |
FM Transmitter: Flashlight-sized worn by speaker. Receiver: With personal hearing aid via DAI or induction neck-loop and telecoil; or self-contained with earphone(s). | Highly portable Different channels allow use by different groups within the same room. High user mobility Variable for large range of hearing losses. | High cost of receivers Equipment fragile Equipment obtrusive High maintenance Expensive to maintain Custom fitting to individual user may be required. | Classrooms Tour groups Meeting areas Outdoor events One-on-one |
Infrared Transmitter: Emitter in line-of-sight with receiver. Receiver: Self-contained. Or with personal hearing aid via DAI or induction neckloop and telecoil. | Easy to use Insures privacy or confidentiality Moderate cost Can often be integrated into existing public address system. | Line-of sight required between emitter and receiver. Ineffective outdoors Limited portability Requires installation | Theaters Churches and Temples Auditoriums Meetings requiring confidentiality TV viewing |
| Source: Rehab Brief. National Institute on Disability and Rehabilitation Research. Washington, DC. Vol. XII, No. 10. (1990). |