What is a telecoil and why do I want one in my hearing aid?
A telecoil or t-coil is a component that is added to hearing aids to expand the function of the hearing system. It is literally a copper wire that is coiled and placed in the hearing device. When it was first introduced it worked with landline telephones, hence the name telecoil. When you have a telecoil, it can “listen” instead of the microphone. The coil inside the hearing aid is sensitive to magnetic fields. If a phone for example has a strong enough magnetic field, the telecoil can pick it up. Not all phones have a strong enough field, so some phones put a matching coil in the receiver. If a telephone has a coil, it will create a magnetic signal to send to the coil in the hearing aid. This allows the hearing aid and the phone to connect via the coils. When this connection takes place, the hearing aid will take the signal from the phone, via the coil, send it to the amplifier to be processed and then present it to the ear via the receiver. All of this bypasses the microphone.