BACKGROUND OF THE INVENTION Portable cellular telephones have gained extremely wide acceptance. One avantage of cellular telephones is that they enable a subscriber to place and receive calls at the same number, regardless of whether he or she is at home, at the office or traveling. For reasons of safety, subscribers who wish to use their cellular telephones while driving often have a special cradle for the telephone installe in their cars to enable"hands-free" use of the telephone. The cradle has a connector that interfaces with a mating connector on the telephone, known in the art as a car-kit connector, so as to convey both electrical power to the telephone and two-way audio signals between the telephone and a speakerphone system in the car. On the other hand, desktop cradles for cellular telephones tyrically provide only electrical power, for the purpose oy charging the telephone battery.

U. S. Patent 4,972,457, which is incorporated herein bv reference, describes a portable hybrid communication system, which integrates a personal computer, cellular transmitter, modem, and speakerphone into a case with a facility for external connections. The system has connectors for attaching a headset, cellular control unit, land te phone line, and additional speakers and microphones. The system does not require or accept a user's ordinary, pocket-size cellular telephone, since the cellular transmitter is an integral part of the overall system.

Wireless telephones, including both cellular telephones and cordless phones, generally communicate using RF transmission and reception. IR wireless phones are also known in the art, however, providing for two-way IR transmission between a wired telephone line and a telephone handset.

For example, European patent application no.

558, 812, which is incorporated herein by reference, describes a ccrdless telephone handset that is linked by a photodiode and LED to a fixed station having an IR transmitter and receiver, coupled to a conventional telephone line. The fixed station is placed on a desk or mounted on a wall, while the handset can be moved around within the room. The use of IR communications, in place of RF, reduces susceptibility to interference and interception of communications and also reduces the exposure of users of the telephone to potentially harmful radiation. There has recently been increasing awareness of the dangers of electromagnetic radiation, and particularly of disease risks due to the high dosage of microwave radiation that cellular telephone users receive.

Sharp Corporation, of Japan, offers the"PMC"line of cellular telephones having an IR communication port.

This port is cesigned for local, very short-range, line- of-sight communication, with a personal computer, for example. It enables the cellular telephone to be used for data communication, typically in order to download information from the computer to an organizer embedded in the telephone. The telephone communicates with its cellular network exclusively by means of a conventional RF transmitter/receiver. The Nokia 9000 series of cellular telephones offers similar capabilities.

SUMMARY OF THE INVENTION It is an object of some aspects of the present invention to provide methods and devices for enhancing the convenience of use of cellular telephones.

It is a fur her object of some aspects of the present invention to provide methods and devices for enhancing the safety of use of cellular te-phones and particularly for reduction of health hazards due to exposure to radio-frequency radiation.

In preferred embodiments of the present invention, a desktop docking station for a cellular telephone comprises a processing circuit to enable remote audio input and output. The docking station includes a cradle for the telephone, with a connector that mates with a suitable connector on the telephone, typically a car-kit connector. The processing circuit of the docking station is coupled to a speakerphone or to a headset or handset, enabling a user of the cellular telephone to use the telephone at arm's length or greater distance without having to hold or support it. The user's hands are thus freed for other activities, such as writing, and the dosage of electromagnetic radiation that the user receives is greatly reduced.

In those preferred embodiments of the present invention in which the processing circuit of the docking station is coupled ro a headset or handset, the coupling is preferably achieved over a two-way infrared (IR) link, most preferably using diffuse IR transmission and reception at both ends of the link. Alternatively, the headset or handset is connected bv a wire to the cradle for the cellular telephone.

There is therefore provided, in accordance with a preferred embcdimen t of the present invention, a docking station for a cellular telephone, including: a cradle, adapted to stand stably on a flat surface, into which cradle the telephone is inserted ; a cradle coupler, which communicates with the telephone so as to receive output audio signals from the telephone and convey input audio signals thereto ; and an audio input/output device, including a speaker and a microphone coupled to exchange the inpu and output audio signals with the cradle coupler, enabling a user to carry on a conversation over the telephone without holding the telephone.

Preferably, the cradle coupler includes an electrical connector, which mates with a mating connector on the telephone, most preferably a car-kit connector.

Further preferably, the audio input/output device enables the user to carry on the conversation while located at a distance greater than arm's length from the telephone. Most preferably, the audio input/output device includes a speakerphone.

Alternatively or additionally, the audio input/output device is selected from a group consisting of a headset and a handset. In a preferred embodiment, the audio input/output device includes a first infrared transmitter and receiver, coupled respectively to the microphone and to the speaker, and comprising a second infrared transmitter and receiver fixed to the cradle and in communication with the cradle coupler, so that the input and output audio signals are conveyed between the E cradle and t :-e audio input/output device bv infrared radiation between the transmitters and the receivers.

Preferably, he infrared radiation includes diffuse infrared radiation.

There is also provided, in accordance with a preferred embcdiment of the present invention, a wireless headset for use with a cellular telephone, including : a microphone, which captures sound produced by a user of the headset and converts the sounds to input audio signals; an infrared transmitter, which generates modulated <BR> <BR> <BR> infrared radiation, preferably diffuse infrared radiation, responsive to the input audio signals so as to convey the signals to an infrared communication device associated the cellular telephone; an infrared receiver, which receives output audio signals in the form of modulated infrared radiation from the infrared communications device associated with the cellular telephone ; and an earphone speaker, which converts the received output audio signals to sound audible to the user of the headset.

The present invention will be more fullRi understood from the following detailed description of the preferred embodiments thereof, taken together with the drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic, pictorial illustration of a docking station for a cellular telephone, in accordance with a preferred embodiment of the present invention; and Fig. 2 is a schematic, pictorial illustration of a docking station and headset for use with a cellular telephone, in accordance with another preferred embodiment of : he present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Reference is now made to Fig. 1, which is a schematic, pictorial illustration of a docking station 20 for a cellular telephone 22, in accordance with a creferred embcdiment of the present invention. Station ^0 comprises a cradle which receives and holds the telephone firmly in place. A cradle connector 28 mates with a car-kit connector 26 (or other suitable connector) or telephone _2, so as to provide power and audio input and output cornect ons to the telephone. Al. ernatively, the docking station may be coupled to exchange audio signals with telephone 22 by any other suitable means, for example, by suitable audio coupling to the built-in microphone and speaker of telephone 22, or by a radio- frequency or infrared link. Docking station 20 may be placed on a table-top, as shown in the figure, or it may be arranged in any other suitable location, such as mounted on a wall.

Connector 28 is coupled to audio processing circuit 30 in a speakerphone unit 36 of station 20.

The circuitry conveys telephone audio signals from the connector to a speaker 32, and receives audio signals from a microphone 34, to be conveyed via the connector to the telephone. Preferably, unit 36 includes user controls (not shown), such as on/off, volume and mute controls, and offers other features as are known in the speakerphone art. As long as telephone 22 is inserted in cradle 24, docking station 20 functions in substantially the same manne_ as a conventional speakerphone.

Optionaliy, docking station 20 also includes a handset 38, which is preferably coupled to audio processing circuitry 30 via a wire 39. Alternatively, the handset is coupled to the docking station by an infrared link, as described in greater detail hereinbelow with reference to Fig. 2. As a further option, docking station 20 also includes a connection to a wired communications network (not shown), such as a public switched telephone network (PSTN), so that the single desktop station can serve for both wireless and wired communications.

Fig. 2 is a. schematic, pictorial illustration of a docking station 40 with a remote headset 50, in accordance with another preferred embodiment of the present invention. The headset includes one or two earphone speakers 60 and a microphone 62, and is coupled to the docking station by an infrared (IR) link. Thus, in place of speakerphone unit 26, station 40 comprises an IR communications unit 42, in which IR processing circuitry 44 takes the place of audio circuitry 30 in processing the signals conveyed to and from connector 28.

Circuitry 44 is coupled to an IR transmitter 46 and an IR receiver 48, which communicate with an IR receiver 56 and an IR transmit-er 58 on headset 50 by means of suitably modulated IR radiation. Processing circuitry 54 in the headset is coupled to convert received IR signals to audio, for output via speakers 60, and to process input audio signals from microphone 62 for transmission by IR transmitter 58. A similar arrangement may be used for coupling handset 38 to docking station 20 (Fig. 1) or to docking station 40.

Preferably, communications unit 42 and headset 50 communicate over a diffuse infrared (IR) link, as is known in the art. For this purpose, IR transmitters 46 and 58, which preferably comprise one or more LEDs, and receivers 48 and 56, which preferably comprise photodiodes, are proviced with suitable optics, most preferably as described in U. S. Patent Application 08/992, 934, which is assigned to the assignee of the present patent : application and incorporated herein by reference. Using such a link, as long as headset 50 (or handset 38) is within a certain radius of station 40, typically about 8 m, communications between the headset and the docking station will be maintained. It is not necessary that headset 50 be in any particular orientation or that there even be a clear line of sight between the headset and the docking station, since the IR receivers will also receive radiation reflected from interior walls and ceiling of a room in which the docking station and headset are located. Alternatively, communication between unit 42 and headset 50 (or handset 38) may be carried out over other types or IR links, as are known in the art.

Further alternatively, telephone 22 itself may be equipped with an IR communications port (not shown in the figures), which is coupled to audio circuit in the telephone and communicates over the IR link with headset 50 without going through docking station 42. In this case, communications unit 42 may be eliminated or, alternatively, replaced by a speakerphone unit, such as unit 36. A suitable type of IR port for such a telephone is described in U. S. Patent Application 09/116,051, which is assigned to the assignee of the present patent application and incorporated herein by reference. Even though the IR port in application 09/116, 051 is described for use in communications between the telephone and a cellular network, the port can easily be rewired and used for audio communications with headset 50.

Although for the sa : te of simplicity of illustration, docking station 20 with speakerphone unit 36 and handset 38, and docking station 40 with remote headset 50 are shown and described as separate embodiments, the different elements of these embodiments are net mutually exclusive. The features and principles described hereinabove may be embocied in a wide range c different combinations and sub-combinations, including a docking station offering both a speakerphone and a remote headset, as well as or instead of the handset. All such embodiments are considered to be within the scope of the presenc invention, and it will be appreciated that the preferred embodiments described above are cited simply by way of example. The full scope of the invention is limited only by the claims.