Field of the invention The invention relates to enabling telephony for users wearing a hearing aid.

Background of the invention Many people having problems with hearing are highly impaired to hear speech in places with demanding acoustical conditions. Therefore most hearing aid manufacturers include means for receiving a signal from an induction loop in the hearing aid since many years. In many places with very demanding acoustical conditions, e.g. in some churches, it is now a commonplace to use small hand-held radio receivers which transducer the radio field to a magnetic field which then by induction can be received at the hearing aid and converted to audio signal.

In a similar manner, many hearing aid users' ability to use a telephone is very limited, partly because the sound originates from a very narrow angle, partly because the sound pressure from a loudspeaker can be rather small. A solution to overcome this problem has been to include means for converting the signal normally output through a loudspeaker of the telephone to to a magnetic field in the telephone. By doing so, the signal quality and therefore also e.g. understandability of speech improves considerably, since the hearing aid does not amplify acoustic environmental noise in so-called T-coil mode. Since the size of the target user group for such devices is rather limited, manufacturing telephones in long series as stipulated by the production line efficiency would be impossible. If the same feature were included in a mainstream telephone, the manufacturing cost would be higher thus reducing the manufcaturer' s profit.

A prior art solution to overcome this problem is to use inductive loop as an accessory that is connected to the phone through a connector at the bottom of the telephone. An example of this kind of accessory is "Nokia Mobile Inductive Loopset LPSl". As can be seen from this kind of an accessory, it is highly impractical since it - by its very nature - increases the cabling that the user should manage, thus being very prone to entangling, which many users may find annoying.

Summary of the invention An objective of the invention is to improve the comfort of using telephony services when wearing a hearing aid device. This objective can be achieved as set out in independent patent claims 1 or 11.

Another objective of the invention is to improve the suitability of a telephone for various user groups, while not substantially increasing manufacturing costs. This objective can be achieved as set out in independent patent claim 5.

Dependent claims describe various advantageous embodiments of the invention.

Advantages of the invention If a cover suitable for a telephone comprises means for receiving a signal; and means for converting the signal to a magnetic field, the magnetic field being suitable for being received at a hearing aid, the user of the telephone does not need to use an "Inductive Loopset" -like solution.

Furthermore, it is much more difficult to forget the cover at home or at office, and such a cover is not that fragile either as an external solution. Since the converting means are in the cover, the distance from them to reception means in the hearing aid is at shortest, thereby providing a better inductive coupling between the converting means and the hearing aid.

If said cover is exchangeable, same telephone can be addressed to different user groups, whereas different user groups may prefer using different kinds of covers for their telephones.

If the means for receiving a signal comprises a spring elastic contact member on a support plate connected to the cover, the support plate further providing an electrical connection to the means for converting the signal to a magnetic field, the design of the cover be more creative since there is no need any more for a fixed contact point at a boundary of the cover.

If a telephone comprises means for passing a speech or alert signal to a cover, a cover according to one aspect of the invention can be used with the telephone. To include means for converting the signal to a magnetic field, e.g. a T-coil, in every telephone of the same type would involve higher manufacturing cost. In most cases this would be in vain, since the T-coil would finally be needed by a relatively small user group only. By using a more generic telephone, users who need hearing aid will also benefit, because their telephones too can be manufactured in long production series, thus pressing down the manufacturing costs .

If a telephone further comprises means for passing a speech or alert signal to an acoustic transducer; and if the telephone is adapted not to pass the speech or alert signal to the acoustic transducer when the speech or alert signal is passed to the cover, the telephone will not disturb a user using a hearing aid by passing same signal first to the loudspeaker and then to the magnetic induction loop.

If a telephone further comprises detecting means for automatically detecting the presence of the cover or of the means for converting the signal to a magnetic field; and means responsive to the detecting means, adapted to: i) automatically change the telephone to pass the electric signal to the cover when the cover is present; and/or ii) automatically change the telephone to pass the electric signal to the acoustic transducer when the cover is not present, the user does not necessarily need to manually change settings of his or her telephone when he or she inserts a cover according to an aspect of the invention.

If a telephone furthermore comprises a cover according to an aspect of the invention, the telephone may then be used for telephony services.

If the means in the cover for converting the signal to a magnetic field are at least 2 mm above a surface of a printed circuit board of the portable telephone, the reflections of the metal coating of the PCB can be reduced. Furthermore, if the telephone is dropped, together with its cover, the probability of the converting means colliding with the PCB can be reduced. Because the cover may at least partially consist of flexible material, the separation can protect the converting means when the cover is being bent.

If the telephone is a portable telephone, especially a cellular phone or a DECT phone, the user of the telephone is not bound to limiting posed by a cable in that where he/he can use his/her telephone.

List of Figures In the following, the invention is described in more detail with reference to the examples in the accompanying drawings in Figures 1 to 3, of which:

Figure 1 illustrates some components of a telephone;

Figure 2 illustrates some parts of a cover for a telephone;

Figure 3 is a section of a telephone with a cover; and

Figure 4 illustrates using the telephone with a hearing aid.

Same reference numerals refer to similar components throughout the Figures.

Detailed description Figure 1 represents a telephone 100. The telephone 100 comprises a Printed Circuit Board PCB 103, on which there is a processing unit 109. An acoustic transducer 105 for producing sound - such as a loudspeaker - may be connected onto the PCB 103, or in a hole of the PCB 103. The processing unit 109 comprises means for controlling the operation of the telephone 100. Telephones are as such very well known, more detailed description can therefore be omitted.

According to one aspect of the invention, the telephone 100 comprises means 107 for passing a speech or alert signal S to a cover 200. As cover 200 is meant any housing of the telephone 100, and especially such one forming at least a part of the upper cover of the telephone 100. Means 107 for passing a speech or alert signal S to a cover 200 can include a connector, a connection pin, or any other means suitable for passing the speech or alert signal S to a cover 200. They are preferably positioned within some cm from the acoustic transducer 105. The reason for the positioning is that the acoustic transducer 105 is, because of anatomical reasons, usually located very close to ear. Because a hearing aid will also be located very close to ear, say, even inside the ear, hence making it favourable to place the converting means 103 close to the ear too, in order to avoid long wiring or other conducting of the signal S it is feasible to put the connection point close to the acoustic transducer 105.

According to one aspect of the invention, the acoustic transducer 105 may be removable. The means 107 for passing a speech or alert signal S to the cover are then preferably connectable to a socket on the PCB which originally was intended for the acoustic transducer 105.

Means 107 for passing a speech or alert signal S to a cover 200 receive the signal preferably from a processing unit 109. Especially if the telephone 100 is an analogic telephone, such as those used for PSTN telephony, it is not necessary that the telephone 100 comprises a processing unit 109 but an amplifier or any other suitable component will do. The telephone 100 further comprises means 109 for passing a speech or alert signal S to an acoustic transducer 105. The telephone 100 may be adapted not to pass the speech or alert signal S to the acoustic transducer 105 when the speech or alert signal S is passed to the cover 200.

The telephone 100 may further comprise detecting means - such as the processing unit 109 - for automatically detecting the presence of the cover 200 or of the means 203 for converting the signal S to a magnetic field; and optionally in addition to this, means 109 responsive to the detecting means 109, adapted to: i) automatically change the telephone 100 to pass the electric signal S to the cover 200 when the cover 200 is present; and/or ii) automatically change the telephone 100 to pass the electric signal S to the acoustic transducer 105 when the cover 200 is not present.

The telephone 100 may be a portable telephone, especially a cellular phone or a DECT phone. Some particular examples of cellular phones include GPS, GPRS, EDGE, UMTS, and CDMA phones, or any combination of these.

Figure 2 illustrates a cover 200 for a telephone 100, comprising means 107B, such as a connector, for receiving a signal S; and means 203 for converting the signal S to a magnetic field, the magnetic field being suitable for being received at a hearing aid 400. An example of the converting means 203 is the T-coil, sometimes known as the tele-coil, especially Surface Mount Device SMD-type T-coil. The means 203 have been assembled onto a support plate 201 which can be a small PCB, for example, by using a holder. Instead of doing so, the means 203 can be fixed to the cover 200 directly. The cover 200 may be exchangeable. This enables the user to replace a traditional cover with a cover according to this aspect of the invention.

The converting means 203 are preferably located at or close to the voice outlet normally used for the acoustic transducer 105.

Figure 3 is a simplified section of a telephone 100 with a cover 200. The means 107B for receiving a signal S comprises an elastic contact member 301, e.g. a spring or a metallic contact leaf, on a support plate 201 which can be a small PCB, for example, connected to the cover 200. The support plate 201 further provides an electrical connection to the means 203 for converting the signal S to a magnetic field.

As an alternative, means 203 for converting the signal S to a magnetic field can be directly connectable to the PCB 103, if the means 203 have suitable contact points. In this manner, the PCB 201 may be omitted.

Preferably the cover 200 is so designed that the distance d between converting means 203 and the surface of the printed circuit board 103 is at least 2 mm.

Figure 4 illustrates the method according to the invention. Means 203 for converting the signal S to a magnetic field are placed into the cover 200, especially in the front cover, of a telephone 100. The converting means 203 generate a required magnetic field which is picked up by the hearing aid 400. Since only a fraction of all telephones need to support a hearing aid, it is an advantage from cost side to place e.g. a T-coil in a clip-on front cover. This is also a good solution from signal-to-noise point of view since the magnetic field is stronger when the distance from the converting means 203 to the hearing aid 400 is at shortest.

The skilled person appreciates that even though the invention has been disclosed in way of some examples, the invention is not limited to these but by the scope of the claims.