If portable systems are used for conference or meeting rooms, the system may serve more than one room. If the listening system provided serves individual fixed seats, then such seats shall be located within 50 ft. Types of Listening Systems - Audio loops and radio frequency systems are two acceptable types of listening systems. Earphone jacks with variable volume controls can benefit only people who have slight hearing losses and do not help people with hearing aids. At the present time, audio loops are the most feasible type of listening system for people who use hearing aids, but people without hearing aids or those with hearing aids not equipped with inductive pickups cannot use them.
Loops can be portable and moved to various locations within a room.
Moreover, for little cost, they can serve a large area within a seating area. Radio frequency systems can be extremely effective and inexpensive. People without hearing aids can use them but people with hearing aids need custom-designed equipment to use them as they are presently designed. If hearing aids had a jack to allow a by-pass of microphones, then radio frequency systems would be suitable for people with and without hearing. Some listening systems may be subject to interference from other equipment and feedback from hearing aids of people who are using the systems.