Note: Descriptions are shown in the official language in which they were submitted.
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Method for establishing a binaural communication link and
binaural hearing devices
The present invention is directed on linking a pair of
hearing devices to form a set of binaural hearing devices.
Such hearing devices may be therapeutic hearing aid devices
for hearing impaired persons or may be hearing devices just
for improving human hearing or for allowing listening to
electronically converted audio signals as e.g. for
telephone ear-sets, ear-sets in airplanes or even noise
protection hearing devices, thereby possibly for active
noise cancellation.
Today known binaural links between a pair of hearing
devices are impaired by the severe requirements at hearing
devices and thereby especially at hearing aid devices with
respect to electric power consumption. There has been
proposed to establish such a binaural wireless
communication link in the RF-frequency band or even in the
microwave frequency band. Thereby satisfyingly small
receiving and transmission aerials may be used, but the
power consumption for the transmitter and the receiver is
considerable.
A communication link approach at lower transmission
frequencies necessitates, whenever audio signals shall be
transmitted via such link, relatively complex encoding and
decoding procedures as e.g. MPEG-codec, so as to result in
high compression of the data being transmitted. Such
encoding procedures nevertheless have the drawback of
significant signal delay normally in excess of 50 msec and
BESTATIGUNGSKOPIE
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are therefore not suited for binaural communication between
hearing devices as here a real-time signal processing is
important.
Other approaches to such binaural communication are based
on wire-bound transmission. This necessitates the appliance
of at least two wires by mini plugs to both hearing devices
of the pair. Handling of a cable with two wires and
especially of respective mini-plugs at the hearing devices
is cumbersome for the individual, especially if such
handling is performed as the hearing devices are already
applied to the individual's ear. Therefore it is an object
of the present invention to propose a binaural
communication link which eliminates the drawbacks mentioned
of wire-based links.
This object is resolved by the present invention by an
approach as it is disclosed in the WO 01/39569 of the same
applicant and inventors and which accords to the US-Patent
Application No. 09/804 848.
Therein the solution of the above outlined problem is
disclosed. According to the present invention there is thus
proposed a method of establishing a binaural communication
link between two hearing devices at an individual by at
least two electric conductors in that one conductor is
established by the individual's body and the at least one
second conductor by a wire.
Thus the individual body with the respective body impedance
is exploited as one of the said conductors so that there
remains, in minimum, a single wire connection to be
established between the hearing devices. Such a single wire
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connection may very easily be handled and plugged in at the
respective hearing devices by the individual.
By such a communication link either control signals to and
from the respective hearing devices, but audio signals too,
be it in analogue or in digital form, may be transmitted
even bidirectionally. In a preferred embodiment there is
thus proposed to bidirectionally transmit electrical
signals between the hearing devices which are linked by the
communication link according to the invention.
In a further preferred embodiment of the inventive method
the hearing devices are not directly mutually linked by the
said wire, but there is provided an electronic unit
interconnected between the hearing devices by the
communication link.
In a further preferred embodiment the electronic unit
interconnected between the two hearing devices by the
communication link according to the present invention
comprises a receiver-/transmitter unit for wireless
communication. Thereby signals received by wireless
communication at such a unit are converted into signals
which are transmitted via the said communication link with
body-conductor to the hearing devices and/or by such an
electronic unit signals received from the said two hearing
devices by the said communication link with body-conductor
are converted into wirelessly transmitted signals. Thus
such an electronic unit operates as a wireless receiver-
/transmit-unit to a remote transmitter-/receiver-unit by
wireless communication for control signal transmission
and/or for audio signal transmission. Such an electronic
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unit may be any RF-link as e.g. a Blue-tooth unit. Thereby
the said receiver-/transmitter unit may be applied, in one
embodiment to one of the hearing devices which is operated
as a master device, the second hearing device as a slave.
In an other more preferred embodiment, the receiver-
/transmitter unit is provided between the two hearing
devices, which are thus operated on equal level of control.
In a most preferred embodiment the advantage of having only
one wire to be connected either directly between the
hearing devices or from the respective hearing devices to
an interconnected electronic unit is exploited by realising
connection of the wire to the hearing devices and/or to
such electronic unit by a magnetic attraction. This leads
to most easily handable plugging. The wire with a
respective magnetic plug at one or at both of its ends may
just be brought adjacent to the respective plug area at the
hearing device or at the electronic unit. Connection will
be practically automatically installed by that wire end
being magnetically pulled onto said plug area at the
respective device.
Thereby and in one preferred embodiment, by said magnetic
attraction there is installed a conductive contact of the
wire to an input tab at the at least one hearing device.
Under a "conductive" material we understand a material with
ohmic current conductance. Thereby such conductive electric
contact may be realised by at least one magnetic member or
ferro-magnetic member itself which provides for plugging
magnetic attraction too.
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In a further preferred mode where for instance electro-
conductivity of a magnetic member or of a ferromagnetic
member does not suffice for satisfying signal transmission,
a conductive contacting is realised by the magnetic
5 attraction - possibly additionally by a magnetic or
ferromagnetic member - by at least one non-magnetic,
metallic contact member, e.g. of aluminum, of copper,
silver, gold, or of stainless steel or copper coated with
gold and/or by conductive polymer.
In a further preferred mode said at least one wire is
applied to at least one of the hearing devices and/or the
electronic unit - mechanically - by magnetic attraction and
- electrically - via a dielectric layer. Thereby a
capacitive coupling is realised. By applying the wire to
the at least one hearing device and/or electronic unit at
both sides of the dielectric layer a conductive capacitance
plate as e.g. of metal is established, thereby completing a
capacitor structure. It is also possible to provide on both
sides namely on the side of the hearing device or of the
electronic unit, if provided, as well as on the side of the
wire a dielectric layer. When such layers are joint once
the connection is established, they form a dielectric
double-layer. With provision of such dielectric layer or
layers cleanability of the contact area is significantly
improved e.g. on the side of the hearing device, where the
dielectric layer may be part and be flush with the outer
surface of the device's shell.
Because by the method of binaural linking according to the
present invention only AC signals within a frequency band
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above 10KHz are preferably to be transmitted, thereby
especially digital signals, it is of no problem to transmit
such signals via a series capacitance. Even if digital
signals are thereby distorted they may easily be recovered
by respective signal processing.
In a further preferred mode where the connection of the
wire to at least one of the hearing devices and/or to the
electronic unit, if provided, is established by magnetic
attraction, this magnetic attraction is additionally
exploited to provide for self-positioning of the wire's
contact area to the hearing device and/or to the unit.
Thereby it becomes not even necessary that the individual
manually and accurately positions the wire's contact area
to the respective contact area of the hearing device or
,is electronic unit, magnetic attraction suffices to mutually
attract such areas and to accurately pull the areas into
mutual correct positioning.
If necessary, by respective selection of polarities of
magnets, on one hand on the hearing device or electronic
unit, and, on the other hand, on the side of the wire, one
can prevent that the wrong wire side is applied to a
respective hearing device or electronic unit contact area.
If there is provided, as mentioned above, an electronic
unit interconnected and communicating with the said two
hearing devices by the communication link according to the
present invention, such electronic unit has preferably a
body contact electrode.
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Such body contact electrode may be conductive, preferably
at lest one of metallic and of a conductive polymer, or may
be capacitive.
In a further preferred mode of realising the method
according to the present invention the two hearing devices
are in-the-ear or outside-the-ear hearing devices, and/or
are hearing aid devices for therapeutic appliances.
In a still further preferred mode of the inventive method
the wire connection and, if provided, also an electronic
unit to be interconnected between the hearing devices is
integrated within a head-worn assembly, thereby preferably
within glasses for the individual. By such assembly,
especially by glasses an accurate positioning of the wire
connection is established without being even visually
recognisable for other persons. In the-above mentioned
embodiment, especially where electric connection of the
glasses-integrated wire is realised by magnetic attraction
to the respective hearing devices, electric contact from
the glasses-integrated wire may be established just by
putting on the glasses. An interconnected electronic unit
even for wireless communication with a remote transmitter-
/receiver unit may also be integrated into the glasses with
a respective transmission aerial.
According to the present invention, there is also provided a binaural hearing
device
set comprising a pair of hearing devices and a communication link between said
devices, characterized by said communication link comprising a body electrode
for
electrically contacting the body of an individual carrying said set at both of
said
hearing devices.
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The present invention is now to be described with the help
of figures, which exemplify preferred embodiments of the
method for establishing binaural communication links and of
binaural hearing devices according to the present
invention. The WO 01/39569 shall be incorporated into the
present description by reference.
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The figures show:
Fig. 1 schematically,,the principle of the method of
establishing a binaural communication link
between hearing devices according to the present
invention and, accordingly, of a binaural hearing
device set according to the present invention;
Fig. 2 schematically and simplified, a set of binaural
hearing devices according to a preferred form of
the present invention and operating according to
the method of the present invention, thereby
establishing bidirectional audio signal and/or
control signal communication;
Fig. 3 in a representation form in analogy to that of
fig. 2 a set of binaural hearing devices
according to the present invention and operating
according to the method of the present invention,
whereat one of the hearing devices is operated as
a master device, the other as a slave;
Fig. 4 in a simplified representation of a preferred
plugging system for establishing to a wire part
of the binaural communication link according to
the present invention electric contact by
magnetic attraction to a counterpart;
Fig. 5 in a representation according to that of fig. 4 a
further preferred plugging system;
Fig. 6 in a schematic form a further preferred wire-
contacting and/or body-contacting arrangement
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applied for establishing the communication link
according to the present invention, and
Fig. 7 glasses with integrated communication link
according to the present invention.
In fig. 1 there is shown, in a most generic and simplified
representation form, the principle of the method according
to the present invention and, accordingly, a set of
binaurally operated hearing devices. At the left side -L-
and the right side -R- ear of an individual there is
applied a left-ear hearing device 1L and respectively a
right-ear device 1R. Conceived as active hearing devices,
each of these devices comprises an electrical to mechanical
converter 3L and 3R being e.g. respective loudspeakers.
These converters 3L,R are operated by respective electronic
units 5L and 5R, which comprise, for digital hearing
devices, customarily a digital processing unit DSP. There
is further provided a communication link between the two
hearing devices 1L and 1R schematically. denoted in fig. 1
by the reference No. 7. This communication link is wire-
bound and therefore comprises at least two wires, which
,link the two hearing devices 1L and iR and thereby
especially their electronic units 5L and 5R.
According to the present invention one of these at least
two wires forming the communication link 7 between the two
hearing devices 1L and 1R is formed by a body conductor 7B,
which is realized by the individual's body between a
contact area 9L, whereat a body electrode 11L at hearing
device 1L contacts the individual's body and a contact area
9R, whereat a body electrode 11R at the hearing device 1R
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contacts individual's body. The body conductor 7B is shown
in fig. 1 in dashed lines with the impedance ZB
representing the individual's body impedance between the
said two contact areas 9L and 9R. Besides of this body
conductor 7B there is provided at least one wire conductor
7w completing the communication link 7. Clearly more than
one communication link 7 may, if necessary, be provided
between the hearing devices 1L and 1R, which leads to
multiple wire conductors 7W with commonly a body conductor
7B.
As will be shown by examples, the communication link 7 may
be operated to perform communication in a selected
direction, e.g. from left to right, or and preferably to
perform communication bidirectionally as shown in fig. 1 by
the double-arrow F.
Further, the communication via the communication link 7
according to the present invention may be for audio signals
converted into a respective electronic form, especially
into digital form, and/or for control signals for the
respective electronic units 5L and 5R. Thereby the
communication link 7 may be established by providing the
wire connector 7W directly interconnecting the two hearing
devices 1L and 1R, at another preferred mode of realizing
the present invention there may be provided a further
electronic unit as shown in dashed pointed lines in fig. 1
and denoted by the reference No. 13 being interconnected
between the hearing devices 1L and 1R and being
electrically connected to at least one, preferably to both
hearing devices 1L and 1R respectively with at least one
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wire connector. An electronic unit is further connected by
a further body contact electrode 1113 to the individual's
body at a contact area 913.
Thereby the electronic unit 13 may comprise (not shown) a
transmitter/receiver unit for wireless communication C with
a remote receiver/transmitter unit (not shown) so as to
receive in wireless communication audio signals and/or
control signals to be transmitted to the hearing devices 1L
.and/or 1R. Additionally or alternatively such
transmitter/receiver unit at the electronic unit 13 may
communicate control signals from and/or towards at least
one of the hearing devices 1L and 1R towards and/or from a
remote control unit. The electronic unit 13 may thus be
conceived as any RF-link, e.g. as a Blue-tooth device.
In fig. 2 there is shown one specific embodiment of
binaurally operated hearing devices with a communication
link 7 according to the present invention. The two hearing
devices 1R and 1L concomitantly operate for specific beam
forming.
It is known that by providing microphones at a
predetermined mutual distance and respective treating of
the electric output signals of such microphones, beam
forming may be achieved based on the fact of mutual phase
difference or time lag with which an acoustical signal from
an acoustical source impinges upon the two microphones.
Such a beam forming is e.g. the well-known "delay and add"
method
According to fig. 2 both hearing devices have respective
microphones 15L and 15R, the outputs thereof being
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operationally connected to respective analogue to digital
converters 17L and 17R.
At each of the hearing devices there is further provided,
as schematically shown with the units 19L and 19R, a
controlled time-multiplexer unit, which is operated by a
respective time control unit 20L and 20R in synchronism. As
schematically shown in fig. 2 in one first time frame '1' a
digitalized output signal of microphone 15L is led, as an
audio signal, via communication link 7 to the input of
digital processing unit DSPR simultaneously with a
digitalized output signal of microphone 15R. Vice versa, in
a second time frame '2' the digitalized output signal of
microphone 15R is led to the input of digital processing
unit DSPL altogether with the digitalized output signal of
microphone 15L. Thereby, staggered in time, the digital
processing units DSP of both hearing devices receive at
their respective inputs digitalized audio signals of both
microphones. Synchronising of the time control units 20L
and 20R is also performed via the communication link
according to the present invention.
Due to the fact that both digital processing units DSP
receive audio information of both microphones, both may
perform beam forming.
Thereby, it becomes evident that it is absolutely possible
to only provide one of the two digital processing units
DSPL or DSPR with digitalized audio signals of both
microphones and thereby to perform beam forming only at one
of the two hearing devices 1L or 1R. In such case
digitalized audio signals may be one-directionally led via
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the communication link 7 according to the present invention
from one hearing device to the other.
One of the two hearing devices acts in such a case as the
beam forming hearing device, which may be said with respect
to beam forming to act as a master hearing device, with
respect to the second hearing device acting as a slave
hearing device.
In fig. 3 there is shown a further preferred embodiment of
a set of binaurally operated hearing devices communicating
by the communication link 7 according to the present
invention. Thereby this embodiment shows an example of one
hearing device, namely device 1L acting as a master with
respect to the second hearing device 1R acting as a slave.
According to fig. 3 only the hearing device 1L has a
microphone or microphone arrangement 15L. Beam forming is
performed after audio signal digitalisation (not shown in
fig. 3) at the digital processing unit DSPL. Via the
communication link 7 according to the present invention, a
digitalized audio signal is communicated via link 7 to the
second hearing device 1R with appropriate phasing e.g.
according to the mutual distance of the two hearing devices
1L and 1R at the individual, and this digitalized audio
signal is directly electrically input to the digital
processing unit DSPR of the hearing device 1R. Thus,
hearing device 1L acts as master hearing device with
respect to a slave hearing device 1R.
It is evident that further master/slave concepts via the
communication link 7 according to the present invention may
be realized also for control signals, one of the two
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hearing devices receiving e.g. by wireless communication
control signals and transmitting control signals to the
slave hearing device. In inverse direction acknowledgement
signals, also being considered as control signals, may be
retransmitted from the slave hearing device to the master
hearing device.
Departing from the main object of the present invention the
communication link 7 according to the present invention has
the tremendous advantage of necessitating only one wire
interconnecting, according to fig. 1, either directly or
via a further electronic unit 13, the two hearing devices
1L and 1R. Thus, only one wire must be plugged to at least
one of the two hearing devices 1L and 1R according to fig.
1, at tap 22L and/or at tap 22R. Although and with respect
to handling plugging-in a hearing device communication link
cable at one or at both of the hearing devices, it is
evident that plugging-in one wire cable is already
significantly easier than plugging-in a multiple wire
cable, a further improvement thereabout is reached by
providing, as will now be exemplified, plugging-in of the
one-wire conductor at at least one or, preferably, at both
hearing devices by magnetic attraction.
Fig. 4 schematically shows a plugging area 22LR according
to fig. 1. If an electronic unit 13 is provided, such
plugging-in system may also be provided to contact unit 13
as is shown in fig. 1 at 2213 by the communication link
wires 7w.
Thereby at least one end of wire 7w and/or the respective
contact area at one or both of the hearing devices 1L, 1R
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and/or at unit 13 are provided with a magnet arrangement.
According to fig. 4 and as an example the end of the wire
7w is provided with a magnet arrangement 24. The
counterpart mechanical contact pad 26 may thereby be of
ferromagnetic material or may be as well a magnet
arrangement.
Thereby, mechanically, the end of wire 7w needs only to be
brought adjacent to the mechanical contact area 26 to be
attracted and positioned in intimate contact therewith by
permanent magnet action.
Nevertheless, this contacting by magnet/magnet contact or
by magnet/ferromagnetic material contact needs not directly
establish the electric contact. In some instances electro-
conductivity and mutual contacting of magnet/magnet or
magnet/ferromagnetic material contacts may not suffice for
electric communication purposes.
An accordingly conceived plug-in arrangement is shown in
fig. 5 in the same schematic representation form as that of
fig. 3. The difference to the embodiment of fig. 4 is that
the magnetic arrangements and counterparts 24/26 are only
provided for mechanical attraction purposes, whereas
electric contacting of the wire 7w to the hearing device
or, respectively, the electronic unit 13 is performed by
non-magnetic contact pads 24e and 26e, e.g. of aluminum,
copper, gold or of stainless steel or copper coated with
gold and/or by a conductive polymer member.
So as to further improve ease of plugging-in the wire
conductor 7w making part of the communication link 7
according to the present invention and by magnetic
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attraction, there may be installed automatic self-
positioning of the contact pads 24e, 26e as shown in fig. 5
e.g. by providing guidance surfaces 28 so as to properly
and automatically position the wire end contact 24, 24e-
This might especially be important in the case where,
according to fig. 5 a pair of locally distinct electric
contact pads 24e and 26e is provided having to be properly
mutually positioned one upon the other.
As will now be shown with the help of fig. 6, electrical
signal transmission from the wire 7W to at least one of the
hearing devices 1L and 1R and possibly even to the
electronic unit 13 as of fig. 1 and/or from the respective
unit (hearing devices and/or unit 13) to individual's body
via the contact area 9 as of fig. 1 needs not necessarily
be established by a conductive contact e.g. by a
metallic/metallic or metallic/electrolytic contact (in case
of body electrodes), but may be established capacitively,
especially for transmitting digital signals representing
audio signals or being control signals,
According to fig. 6 one end of the wire 7W making part of
the communication link according to the present invention
is formed by a conductive plate as by a metal or conductive
polymer layer 30 embedded in an isolating plugging
arrangement 32 as schematically shown. On the opposite
side, thus be it on one or both of the hearing devices or
on the electronic unit 13, there is provided a second
conductive plate as by a metal or conductive polymer layer
34, which is covered towards the outside by dielectric
material, e.g. by a layer 36 of dielectric material. This
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layer may be unitarily formed the,shell or housing of the
hearing device considered or of the electronic unit 13. By
bringing the conductive plate 30 in intimate contact with
the surface of the dielectric layer 36, conductive plate or
layer 30, dielectric layer 36 and conductive plate or layer
34 form or establish a capacitor in series with wire 7w and
operationally connected, as schematically shown, e.g. to a
preamplifier stage 38 at the hearing device or at the unit
13. Especially for transmitting digital signals, even if
such digital signals are distorted by the capacitive -
30/36/34- electric link, it is of no problem to recover the
digital signal e.g. at the preamplifier stage 38.
As further shown in fig. 6 additionally or instead of
capacitively coupling the wire 7w to the electronic unit at
unit 13 and/or to at least one of the hearing devices 1L,
1R also the respective body contact electrode as of 11 of
fig. 1 may be conceived as a series capacitance electrode.
Thereby, at electronic unit 13 or at at least one of the
hearing devices 1L, 1R the body contact electrode comprises
a conductive plate as a metallic layer or a layer of
conductive polymer 40 electrically connected to the
respective electronic unit, as according to fig. 5 to
preamplifier stage 38. The conductive plate or layer 40 is
covered by a dielectric layer 42 in analogy to the
explanations given with respect to dielectric covering of
conductive plate or layer 34. By contacting the
electrolytic conductance body BO of the individual so as to
establish the body conductor 7B of fig. 1, there is again
formed a series capacitance 40/42/BO.
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Providing the dielectric material layers 36 and/or 42
additionally improves cleanability and prevents electrode
corrosion.
It is perfectly clear to the skilled artisan that a
capacitive signal coupling as shown in fig. 6 may also be
realised by covering the other conductive plate 30 by a
dielectric layer or by covering both conductive plates 30
and 34 by such dielectric layers, thereby establishing a
double-layer dielectricum. Thereby, as .a very intimate
contact of the surfaces establishing a series capacitance
coupling should be realized, an electroconductive gel may
be applied between these surfaces to be contacted, e.g. a
gel as is used or applied to cardiographic electrodes.
Bringing the parts to be contacted into mutual intimate
contact so as to establish the series capacitance may be
realized in any known way, as by clip-fixation, bayonet
fixation etc. Nevertheless, in a most preferred embodiment,
this contacting is realized, as shown in fig. 6, by
magnetic attraction too.
In fig. 6 both parts to be contacted are provided with
respective magnet arrangements 24a and 24b. If both these
parts are provided with permanent magnets, as shown in fig.
6, by selection of the respective direction of polarity P
one may prevent that the wire 7w may be brought into
contact at a predetermined contact area, be it of a hearing
device and/or of the electronic unit. With the direction of
polarities P selected according to fig. 6 the two parts are
attracted, whereas if the polarity P e.g. at the plug 32 of
wire 7w is inverted as shown in dashed lines, it will not
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be possible to contact the plug 32 to the area as shown in
fig. 6 due to magnetic repulsion.
Instead of establishing a capacitive contact to the
individual's body BO as was explained before a conductive
contact member may directly be applied and thereby e.g. for
improving comfort to the individual especially a conductive
member of conductive plastic material, especially of
conductive polymer.
In a further preferred embodiment of the present invention
and according to fig. 7 the wire 7W is integrated into
glasses. Thereby, the wire 7W is contacted with the
respective right-hand and left-hand hearing devices (not
shown in fig. 6) at schematically shown contact areas 45,
which preferably are realized for establishing contact by
magnetic attraction, as shown in the figs. 4 to 6. If
provided, an electronic unit 13 may also be integrated into
the glasses. Thus, by simply applying the glasses, the
communication link 7 according to the present invention
between the binaurally operated hearing devices is
established, which is largely facilitated by conceiving
contacting at the areas 45 to the respective hearing
devices, as was described, by magnetic attraction.
