A compatible telephone generates a magnetic field that can be picked up by turning on a T-switch to activate the telecoil in a hearing aid. The Hearing Aid Compatibility Act of 1988 mandates that all telephones manufactured in the United States from 1989 on should be hearing aid compatible. Hearing aids compatible could be headphones as well, but telephones are used the most. The majority of non-portable phone, a few remote phones and a few cell phones in the United States are sold nowadays as hearing aid compatible. The meaning for this is now when you answer the phone, what is outputed is not only the sound of the person on the other line but also a magnetic signal which represents the sound. All of the older telephones were hearing aid compatible because they used these magnetic signals, but nowadays these new telephone which are built a few years ago are not hearing aid compatible because they didn’t use the magnetic signal when they were built. When a person uses a hearing aid compatible telephone it improves its ability to hear on the telephone so much more. It is very important that every cell phone is a compatible telephone with the extremely fast development of the technology, people would want that everyone is up to date and able to consume it.