Transmission system for use in call and/or access control device to transmit electromagnetic audio frequency signal toward earphone of hearing impaired person, has induction coil whose turns are formed in form of printed circuit on board

摘要

The transmission system has a generation unit (1) including an audio source (10) to deliver an electric audio frequency signal with an effective intensity equal to 1 A. An induction system (3) transmits an electromagnetic signal whose frequency corresponds to frequency of the electric audio frequency signal. The induction system includes an electromagnetic induction coil whose turns are formed in the form of a printed circuit on a rigid printed circuit board. The induction system is applied against a plate made of metal such as stainless steel. An independent claim is also included for a call and/or access control device for hearing impaired person.