1 Communication system and hearing device Definitions : • Throughout the present description and claims we understand under the term "hearing device" a device which may be worn by an individual at one or at: both cars. The hearing device comprises at least one acousti ca 1 -to-e lectrical converter unit. Such a unit, is customarily formed by a microphone unit. 11 the hearing device is conceived to be worn at both ears oi an individual and an acoustical-to-olcctrica! converter unit is provided at each part of: the hearing device worn at the respective ears and further there is established a short range communication link between these two parts of the hearing device, then a hearing device is a binaural hearing device in its most general, sense. The hearing device has further at least one signal processing unit the input thereof being operationally connected or at least operationally connectable to the output of the input acoustical-to-electrical converter unit. Again if the hearing device is to be worn at both ears of an individual, signal processing units may be provided at both parts of the hearing device at respective ears. Further the hearing device has at least one oil ectrical -to-mechanical output converter the input of which being operationally connected or operationally 2 connoctab.l.e to the output of the input acoustical to e 1 ectrleal converter. Aqain if the hearing device is conceived to be worn at both ears of an individual such electri.ca I .-to- mechanical converter may be provided at one or at both parts. Such electrical-to-mechanical converter may e.q. be a loudspeaker unit or a coupling member for nioohan i ca 1 Ly stimulating a part, of an individual's i nner ear. Such hearing device may be a device just for improving or facilitating hearing ability of a not hearing impaired individual, e.g. in acoustical surroundings which may render perception of specific acoustical signals difficult or may be devices for the protection of an individual's ear from excessive acoustical stimuli etc. or may be hearing aid devices by which (or hearing impaired individuals normal hearing is re- established as far as possible. Hearing devices may be or comprise parts to be worn by an individual outside the ear, inside the ear and thereby also completely in the ear channel. • We understand under a "listening device" a device which comprises an output electrical-to-mechanical converter unit for stimulating hearing of one or: more than one individuals. A listening device may thereby be just a loudspeaker unit whereby, as outlined above, a hearing device too is a specific type of such Listening device. • We understand under an "audio representing signal." an electrical signal which has been generated by converting and possibly further signal treating e.g. comprising filtering, amplifying etc. departing from an acoustical signal. When a signal is established to be an "at least, audio signal representing signal" this means that such signal may additionally comprise program data and/or control data etc., i.e. other types of signal content. • We understand under a "signal booster unit" a unit which receives an input signal and generates and outputs an output signal which is the improved input signal, improved e.g. with respect to signal-to-noise ratio, to frequency content, to power, etc. • We understand under a "router unit" a unit which receives an input signal and outputs at least: two output signals which are equal to the input signal. Such router unit may comprise one or more than one signal booster units so as to improve the signals as output with respect to the input signal. • We understand by one point being "connectable" to a second point that such connection between the two points is one possibility out of more than one possibility. Thus additionally to the option of 4 connecting these two points they may be possib.ly disconnected and one point or both points may be connected to a third point etc. The skilled artisan perfectly knows control and switching ability to establish such "oonnectability". The present invention is directed to a communication system as well as to a hearing device. [t; is an object of the present invention to widen the scope of use of hearing devices. This object is achieved by a communication system according to the present invention, which comprises a wireless transmitter and a wireless receiver whereby the transmitter is built into a hearing device to be worn at one or at both ears of an individual. Thereby the hearing device has an input acoustical-to-eLectrical converter unit and an output electrical-to-mechanical converter unit, as well as a signal processing unit, operationally interconnected between the acoustical-to-electrical and the electrical-to- mechanical converter and processing audio representing signals. The wireless transmitter is operationally connectable to the output of the input converter unit. The communication system further has a receiver which is remote from the hearing device by a distance which is larger than any distance between two areas at one single individual. 5 The transmitter and the receiver form commonly a wireless communication link at least for audio representing signals. Establishing a wireless communication link from a remote transmitter to a hearing device comprising a receiver and performing communication in a wireless manner is known e.g. from the DE 100 300 915 according to.' which such communication is established by using Bluetooth technology. in opposition, the present invention resides on the fact of establishing a wireless communication departing from a hearing device as worn by an individual towards receiver unit remote from such individual, thereby transitu tting via such wireless link audio representing signals. By such a communication system and as will be evident from the following description and claims a very wide range of new uses for hearing devices is opened thereby also improving hearing ability of one or more than one individual. In an embodiment of the communication system according to the present invention the receiver which is, as was addressed, farer remote from the hearing device with the integrated transmitter than to be possibly worn by the same individual wearing the hearing device, has a wire output and is a part of a further communication link for the addressed at least audio representing signals. Thus downstream the remote; receiver a wire communication link is established to further transmit the at least audio 6 represe n t i n g signa.1 , p o ss.1 b 1 y aceording Ly processed, which was received by the receiver and from t:ho hearing deviee integrated transmitter. In a further embodiment of the present invention the wireless communication link which is established between the hearing device and the addressed remote receiver is only a part of further communication link which additionally has at least one of a further wireless communication link, and of a wire bound communication link respectively for the at least audio representing signal. Thus the wireless communication link between the hearing . device integrated transmitter and the remote receiver is here only part of a wider communication network which may comprise additional links of wireless and/or wire bound typo. In an embodiment of the present invention the addressed remote receiver has an output which is operationally connectable to an input of an electrical-to-mechanical converter. Thus in this embodiment audio representing signaLs which are transmitted over the wireless communication link, between hearing device integrated transmitter and remote receiver, are, possibly via additional wireless and/or wire bound communication links and possibly differently processed according to the respective communication links, finally communicated to an electrical-to-mechanical converter unit whereat they are reconverted in hearing stimulating signals for one or more 7 than one individuals, exposed to such mechanical signals. The electrical-to-mechanicai converter unit addressed may thereby be a loudspeaker unit for a group of individuals or may be as will, be addressed later an electrical-fo- rnochan i.eal converter unit as customarily integrated into hearing devices. Thus it becomes already yet apparent to the skilled artisan that within the frame of the present invent: ion a hearing device to hearing device communication system becomes possible whereby such communication system is wireless at least, at: one of the participating hearing dev Ices. Consequently in one embodiment of the present invent;.! on the just addressed electrical-to-mechanical converter unit the input of which being operationally connectable to the output of the remote receiver, forming together with the hearing device integrated transmitter the addressed wireless communication link, is built or integrated into a further hearing device which is to be worn at one or at both ears of a second individual. Thereby the further hearing device has again an input acoustical-to-electrical converter unit and the addressed electrical -to- mechanical converter unit, the input of which being operationally connectable to the output of the addressed remote receiver, being'in fact the output electrical-to-mechanical converter unit of the further hearing device. Thus, as was already addressed, the hearing device with the integrated transmitter may wirelessly communicate via the 8 remote receiver with an output electrica 1-to-mechanica i. converter unit: of a further hearing device to be worn by a second Individual. Thereby such second individual wearing the second hearing device may be arbitrarily remote from the .individual wearing the hearing device with the integrated transmitter. The further individual may thus be in the same room as the first individual wearing the hearing device with the integrated transmitter, may be in a neighbouring room or may be at any other remote distance world-wide and distant from the said first individual.. In an embodiment of the communication system as was just addressed, the remote receiver which forms, together with the hearing device integrated transmitter, a wireless communication link, is itself integrated into the further hearing device. Thereby wireless communication Crom transmitter to receiver is established directly between at. least two hearing devices. As was addressed above the wireless link from hearing device integrated transmitter and remote receiver may only be a part of a further communication link which may include a wide area communication system - WAN -, a local area communication system - LAN -, a signal booster unit, a router unit, etc. In an embodiment of the communication system as of the present invention the wireless communication link between 9 hearing device integrated transmitter and the addressed remote receiver is performed by frequency modulation (FM) thereby including any known and suitable type of such I'M modulation in its most generic meaning, or by any digital modulation scheme such as phase shift keying (PSK), Q-ary amplitude modulation•(QAM), ect, or is established making use of ultra-wide-band technology (UWB). Thereby an appropriately long communication range, small transmitters and possibly receivers, small power consumption and small transmitted eLectro-magnetic powers may be realized which latter is to be considered in context with possible harm of electro-magnetic fields to individuals exposed thereto. Still in a further embodiment of the communication system according to the present invention both hearing devices which were formerly addressed have respectively a receiver and a transmitter integrated. The one hearing device to be worn at one or at both ears of the one individual, has, additionally to the transmitter, a wireless receiver with an output which is operationally connected to the input: of the electrical-to-mechanical converter unit of this one hearing device. The further hearing device to be worn at one or both ears of a second individual has a wireless transmitter - additionally to a receiver •- which is connect.able to the output of the input acoustical-to- electrical converter unit of this further hearing device;. The w.i reless transmitter at this further hearing device and the wireless receiver at the one hearing device allow a communication link to be established for at least audio 10 representing signals, from said transmitter of the further hearing device to the receiver of the one hearing device. Thus by both addressed hearing devices having a transmitter as well as a receiver a bi-directional communication becomes possible for the addressed at least audio representing signals .• In a further embodiment of the communication system according to the present invention and conceived as was just discussed the output of the acoustical-to-elect.ri.cal converter unit of the one and of the at. least, one further hearing devices are operationally connected to inputs of a computing unit. The computing unit generates in dependency itrorti signals which are input to the addressed inputs of the computing unit, at least one computing results at least audi.o representing signals at an output. The output of a computing unit is operationally connected to the input of at least one of the wireless receivers which are provided at the one and the at. least one further hearing devices. Further, the output of this addressed at least one wireless receiver is operationally connected to the input of the output electrical-to-mechanical converter of at least one of the one and of the further hearing devices. Thus computing unit receives from at least two hearing devices respectively perceived audio representing signals. From these at least two input signals a result audio representing signals is computed. This result audio representing signal is retransmitted to at least one, 11 possibly to both hearing devices so that at least one, possibly both hearing devices transmit to the respective individuals, via their respective oicotri cal-to -moohan.i cal output", converter unit, a signal which results from computing acoustical signals perceived at both or at least two hearing devices. 'Clearly the retransmitted audio representing signal will be an improved signal with an improvement which results from computing commonly both input, signals to the computing unit. Cn the just addressed embodiment the output of the addressed acoustical-to-electrical converters are operationally connected to the inputs of the computing unit. In one embodiment this is performed in that at .'least one of the addressed operational connections comprises the wireless transmitter .of the respective hearing device. With ari eye on a further embodiment oi: the communication system according to the present invention, which incorporates the just addressed computing unit, the computing unit performs a selection between the signals which are applied to its inputs and according to at least one selection criterion. Such selection criterion may e.g. be signal-to--noise ratio. The computing unit thereby generates at its output an output signal which accords to one of the input signals as selected. The computing unit further controls at least one of the el ectrical-to- mechanical output converter units, provided at the one and the further hearing devices to be operationally connected 12 to the output; of the computinq unit. Thus once the computing unit has selected, out of the input signals a "best-suited" signal, it is this best suited signal which is retransmitted to one or both or all hearing devices participating in the communication system. l.n a further embodiment of the communication system according to the present invention and following up the embodiment just discussed, the computing unit performs signal selection dynamically in time. This means that whenever the input signals change the select: ion of the "best-suited" signal may change as well. Analogically dynamic selection may be performed upon variation in time of the selection criterion. Thus during a first time span signal-to-noise ratio may be selection criterion whereas in a second time span e.g. loudness of acoustical signals may be the selection criterion. In a sLi.1.1 further embodiment of the communication system according to the present invention and still departing from an embodiment with the computing unit as was addressed above, the computing unit may generate an output signal which is not a selection between the input signals as was just discussed, but which is an audio representing signal depending on both input signals. Thereby generically the information increase which is achieved by evaluating two or more audio representing signals is exploited so as to generate a combined signal which is improved relative to each input signals considered per se. 13 Thus I.he computing unit may e.g. bo conceived to per form beam forming. Kxploiting input signals which in fact come from remotely located hearing devices, which are mutually distant far more than multiple microphones might be distant in a single hearing device, leads to improved possibilities of beam forming. As the communication system according to the present invention making use of the computing unit clearly may incorporate more than two hearing devices with thei r respective acoustical-to-electrical converters, it becomes clear that computation may be performed with respect, to the output signals of more than two of these acoustical-to- eleetri.cal converter units, which further largely increases the possibilities of improved signal processing. In a still further embodiment of the communication system according to the present invention communication from one hearing devi.ee to a remote further hearing device may be performed in a manner hopping from one hearing device to the next in a chain of hearing devices. Kach of the intermediate devices forms a signal booster unit, possibly without the respective individual becoming aware that its hearing device is being used as signal booster unit. To do so the system comprises more than two hearing devices. A transmitter of a first hearing device 'is 14 operationally connected to the output or its input acoust Ical-to-olectrical converter unit. The output of: the addressed transmitter is operationally J inked by the wireless link to the receiver of the second hearing device. The output of this receiver is operationally connected to the input, of the transmitter at the same hearing device so that .in fact the signal received by the receiver is looped to that transmitter. The output of the transmitter of the just addressed hearing device is operationally linked, including wireless communication, to the receiver of a third hearing device. Thus transmission hopping from one hearing device to the next available one is exploited to bridge a large distance from one hearing device to a remote or tar remote target .hearing device. • Wjth an eye on the communication system according to the present:, invention incorporating two hearing devices, in a further embodiment more than two hearing devices participate in such communication system, in a further embodiment of the communication system according to the present invention the one or at least one of the hearing devices is a hearing aid device. In a further embodiment the one or the two or more than two hearing devices is or are outside the ear hearing devices and/or in the ear hearing devices and/or completely in the ear canal hearing devi.ces. A multiple hearing device communication system may incorporate all the variety of different types of hearing devices, thus e.g. hearing 15 devicer. for normal hearinq individuals, hearing aid devices, binaural hearing devices, provided as outside the ear and/or as in the .ear and/or as completely in the ear canal device types. Under a further aspect of the present invention it is proposed a hearing device to be worn by an individual at one or at both of its ears which comprises an input uoousfical-to-electrical converter units/an output o l.ecf.r i.cal-to-mechani.cal converter unit and a wireless transmitter. The input of the wireless transmitter is operationally connectable to the output of the input acousfLeal/mechanical converter unit whereby the transmitter generates a wirelessly transmitted signal for a transmission range of at Least 2m. Thus this hearing device allows reception of signals from the wireless transmitter in a range of at least 2m which is normally significantly larger than the range between devices worn at one individual's body as e.g. binaural devices. In a further embodiment of the hearing device according to the present invention it comprises a wireless receiver. The output: of such receiver is operationally connected to the input of the output e'lectrical-t:o-mechan.i.cal converter unit. In a still further embodiment of the present invention the transmitter generates transmitted signals using carrier-based analog or digital modulation schemes such as frequency modulation (FM), phase modulation (e.g. PSK) or amplitude modulation (e.g. QAM) or based on 16 carrierloss ultra-wide band techniques, (UWB) employing e.g. on/off keying (00K), pulse position modulation (PPM) or pulse amplitude modulation (PAM). The present: invention shall now be exemplified with uhe help of figures and by examples. The figures show: Fig.l schematically and simplified by means of a functional bLock/signal flow diagram, the principle of a communication system according to the present invention including a hearing device according to the present invention; Fig. '?. .in a simplified schematical representation a further embodiment of the present invention; Fig. 3 still in a simplified schematical representation a communication system with hearing device according to the present invention; Fig. 4 in a schematic and simplified representation a further embodiment of the communication system according to the present invention including a hearing device according to the invention including a network; Fig. 5 Still schematically and simplified by means of a functional block/signal flow diagram, a communication system according to the present, invention for communication between at least two hearing devices; Fig. 6 schematical and simplified a further at least two hearing devices communication system according to 17 the present; invention with direct wireless communication links; fiq. 7 in a representation according to that of fig. 6 a further embodiment of the communication system according to the present .invent-.ion, whereat the communication is established by at least two wireless communication links via a signal booster unit ; Fig. 8 in a diagrammatic representation and as an example a complete communication system according to the present invention; Fig. 0 by means of a simplified functional block/signal flow diagram, a further embodiment, of a communication system according to the present; invention whereat a master device is selected according to specific criteria; Fig. 10 in a simplified functional block signal/signal flow diagrammatic form, a hearing device according to the present invention with transmission and receiver ability and as e.g. applied to the communication systems as exemplified in the fig. 9, 11 and 12; Fig. 11 in a simplified functional, block/signal flow diagram a communication system according to the present invention for device hopping communication between remote hearing devices; Fig. 12 in a representation according to that of fig. 11 a communication system according to the present 18 invention whereat, remote] y perceived acoustical signals are commonly processed. Fig. 13 simplified'and in a schematical representation by means of a signal flow/functional block diagram a technique for the communication system according to the present invention to account for effects caused by different spatial location and orientation, as well as for Individual effects of hearing devices of the system. In tig. 1 the communication system according to the; present invention is shown in a first realization form and rather in a minimum configuration. The communication system comprises a hearing device 1. 'The hearing device 1 comprises an acoustical-to-e l.ectrica 1 converter unit 3. The electrical output of unit 3 is operationally connected, via a signal processing unit 5, to the input of an output electrical-to- mechanical converter unit 7. Input, to device 1 are surrounding acoustical signals Ai, output from device 1 'a mechanical signal Mi as a stimulus to an individual's - la - ear. The hearing device 1 as an essential part of the communication system according to the present invention has 19 a transmitter unit 9 whereat audio representing signals, which may be dependent from input acoustical, signals A-L, are input. By transmitter unit 9, such audio representing signals are converted into wireless transmission signals WL. in opposition to the case where, for binaural, hearing devices, a signal transmission, thereby also possibly in a wireless manner, is performed on short distance, i.e. from one ear of an individual to the other, according to the present invention the transmitter unit. 9 generates a signal WT. for longer range transmission e.g. for a range ot at least; 2m, larger than necessary, for reaching any target area at the individual la. This is realized e.g. by larger transmission power, suitable modulation schemes, channel coding or broad band transmission techniques such as e.g. by ultra wide band (UWB) --type transmission. Especially, if higher transmission power is used, care should be taken to install a proper directivity of signal transmission from transmitter unit 9, not to .load the individual la with too high electromagnetic power. By the wireless transmission signal WL at least a part of a communication link CL is established between the hearing device 1 and at least one listening device 11. 20 Via the communication link CL which is formed by or which comprises the wireless communication Link WL, at least audio representing signals perceived at the one individual la with the he.lp of the hearing device ] are transmitted to at least one listening device 11 remote from the individual la. 'there the device 11 stimulates hearing of at least one further individual 11a. The communication link CL consists, in minimum configuration, just of the wireless communication link WL established from the transmitter unit 9 of the hearing device 1 to a respective remote receiver unit 13 at the Listening device 11, schematically shown in fig. 2. Thereby the communication range is restricted to the wireless transmission range of: the transmitter unit 9. A scenario in which such "direct" wireless communication may be useful, is schematically shown in fig. 3. In a conference room speech of a speaker individual la wearing the hearing device 1 or of an individual la which is located in a particularly good acoustical situation, is wire1, essly linked to listening devices 11 i to 11,] of further individuals llai to lla-i. Thereby the outstanding acoustical perception at the individual la is shared with the acoustically less favourably positioned individuals lla! to lla4. 21 A situation in which the system as of fig. 3 may also be useful is e.g. when a group of individuals 11 ai to llaoa to A2