Patent ID: 7426279

Claim:
Apparatus for communicating voice or data signals by electromagnetic induction from a signal producing device to an external hearing aid related device, comprising: (a) a sending transducer in said signal producing device, said sending transducer having a substantially toroidal core of permeable material surrounded by a driving winding; (b) said substantially toroidal core having an air gap of predetermined circumferential angular extent; (c) said sending transducer further having a pair of shaped pole faces formed at the circumferential extremities of said substantially toroidal core adjacent to said air gap, said pole faces giving rise to a fringing field; and (d) whereby upon production of voice or data signals by said signal producing device, said sending transducer produces a corresponding fringing field which may be applied to an external hearing aid related device thereby allowing replication of said voice or data signals by said external hearing aid related device.