WO2005055566A1

WO2005055566A1 - Sonic data communication between mobile phones

Info

Publication number: WO2005055566A1
Application number: PCT/EP2003/013764
Authority: WO
Inventors: Oluf Bagger; Jochen Marx
Original assignee: Nokia Corporation
Priority date: 2003-12-05
Filing date: 2003-12-05
Publication date: 2005-06-16
Also published as: AU2003296615A1

Abstract

A mobile phone in which the in-built microphone and loudspeaker are used to produce a sonic data carrying signal for exchanging digital data with another mobile phone in relative close proximity. The DSP unit acts as a modem that is connected to both the in-built loudspeaker and in-built microphone to modulate and demodulate the digital data. The sonic data signal travels from the loudspeaker of the sending phone over the air to the microphone of the other mobile phone. Phone numbers, color images, ringing tones and other user data that are typically stored in a mobile phone can be transferred without with mobile phones that are not equipped with IR transceivers or short range RF transceivers. The invention also relates to a method of dialing a phone number stored in a mobile phone on a landline phone, and to a mobile phone for use in such a method.

Description

SONIC DATA COMMUNICATION BETWEEN MOBILE PHONES

The present invention relates a method of sending data from a first mobile phone to a second mobile phone in the vicinity. The invention also relates to a mobile phone that is capable of transmitting data to another mobile phone in the vicinity. The present invention also relates to a method of dialing a phone number stored in a mobile phone on a landline phone, and to a mobile phone for use in such a method.

BACKGROUND ART

There is an increasing need for wireless data exchange between mobile phones, because they handle more and more data. When two persons both carrying a mobile phone meet, exchanging e.g. addresses and telephone numbers by keying the data in is cumbersome, and often the address data to be exchanges already stored in one of the phones . Transferring a phone book entry by means of a so called V-card is practically only possible if both phones are equipped with compatible IR transmitters .

US 5,706,110 discloses a method of data exchange between objects terminals such as mobile phones or personal digital assistants (PDAs) using an infrared transmission medium, as defined in the IrDA standard. Since IrDA devices use infrared light, they depend on being in direct line of sight with each other. Further, infrared transceivers are not common for all types of devices, in particularly not on low end devices for cost reasons . A substantial part of the mobile phones presently on the market are not equipped with infrared transceivers.

US 6,287,200 discloses a method of exchanging data between terminals, such as mobile phones and PDAs using RF signals in accordance with the Bluetooth standard. RF signals have the advantage over IR signals that a direct line of sight is not required for the communication link. A disadvantage of using RF signals is that the use of the radio frequency band is regulated and a license is a prerequisite for using of radio frequency signals. Further each of the terminals involved needs to be equipped with dedicated radio transmission equipment capable of sending and receiving signals in accordance with the Bluetooth standard. For e.g. costs reasons, only a minor part of the mobile phones presently on the market is equipped with a Bluetooth transmitter.

WO 00/01099 discloses a general purpose ultrasonic data transmission system. Ultrasonic transmission allows high data transfer rates and the signal does not disturb any persons nearby since it lies outside the human audible range. However, mobile phones are presently not equipped with ultrasonic transceivers, and ultrasonic transmission of data is therefore not an option for low end mobile phones for costs reasons, because of the additional costs .

Data communication via sonic signals between devices such as a modem and telephone is known as so called acoustical coupling. The receiver of the telephone is placed in a cradle on the modem. The signals are transferred over a short distance between the two loudspeaker-microphone sets. US 5,063,590 discloses an acoustic coupler for use in connecting a data modem to a typical telephone handset . Acoustic couplers can nowadays only be found in museums since virtually all modern modems have a cable connection to the PSTN.

It is also possible to transmit data between mobile phones over the cellular mobile network via e.g. SMS or MMS. However, the amount and type of data that can be send this way is limited, in particular for SMS, and for MMS there are relatively high charges for sending e.g. a color picture via the network.

A substantial group of mobile phone users uses prepaid cards to enable their mobile phones . Calls can not be placed when the credit stored on the card is used up. If a user wishes to place a call anyway and a landline (pay) phone is available the user can retrieve the number to be called from the phone book in the mobile phone, and while it is shown on the display of the mobile phone, manually enter the phone number into the landline phone. This procedure is though relatively cumbersome.

US 4,995,077 discloses an automatic dialer, that is used to dial a stored telephone number by playing a sequence of DTMF tones over a loudspeaker in the automatic dialer. The loudspeaker is placed close to the microphone of the a landline telephone and the DTMF tone sequence is transmitted to the telephone central which in turn establishes a connection to the number concerned.

DISCLOSURE OF THE INVENTION

On this background, it is an object of the present invention to provide a method of transmitting digital data from a first mobile phone to a second mobile phone that can be implemented without any substantial changes to the basic hardware of a mobile phone.

This object is achieved in accordance with claim 1 by providing a method of transmitting data from a first mobile phone having an in-built microphone and loudspeaker to a second mobile communication terminal having an in-built microphone and loudspeaker, comprising the steps of - placing the first and second mobile phone within audible range from one another, the first mobile phone modulating digital data into an analogue signal that is fed to the in-built loudspeaker to produce a sonic signal, the second mobile phone picking up said sonic signal with the in-built microphone and demodulating the sonic data signal into digital data.

The modulated sonic signal travels through the open air space between the phones. A user of the first phone is accordingly enabled to send data, e.g. phone book entries, ringing tones or color images to a user of a second mobile phone in the vicinity without the need for the two mobile phones to be equipped with in IR receivers or Bluetooth receivers . The method can therefore be carried out with low end mobile phones.

The effective range is up 2 meter, depending on the amount of ambient noise during transmission and the presence of sound dampening objects in the sound path.

The sonic signal is a preferably a narrow band signal that lies within the human audible range, most preferably in the voice band range .

The transmission is preferably initiated by the first mobile phone sending a pilot tone for synchronizing the transmission. The pilot tone may comprise a sequence of DTMF tones. Asynchronous transmission is though also possible.

DTMF tones sequences can also be used in the sonic signal to transmit the data in sound waves over the air, in particular in high noise environments . Frequency shift keying (FSK) or amplitude modulation can used to modulate the data.

Alternatively phase modulation, preferably differential phase modulation can be used to modulate the data. It is also possible to use phase-shift keying (PSK) or quadrature amplitude modulation (QAM) to modulate the data.

Preferably, error correction is applied by a parity check, Reed-Solomon error correction codes and/or Viterbi coding.

The sonic signal can be encoded in accordance with an analogue modem standard, preferably in accordance with the Bell 103M or 212A standard, the ITU V.21, V.22, V.22bis, or V.23 recommendation.

For security reasons the sonic signal may be encrypted using a combination of a private key and a public key.

It is yet another object of the present invention to provide a mobile phone that is capable of transmitting and receiving data to and from another mobile phone without adding any hardware to the basic configuration of a mobile phone. This object is achieved in accordance with claim 17 by providing a mobile phone comprising an in-built microphone, an in-built loudspeaker, a processor unit, a memory interfacing with the processor unit, a modulator interfacing with the processor unit and with the in-built loudspeaker. The modulator is capable of converting digital data stored in the memory into signal for the loudspeaker to produce a sonic data carrying signal. The phone further comprises a demodulator interfacing with the processor unit and with the in-built microphone. The demodulator is capable of converting a sonic data carrying signal picked up by the in-built microphone into digital data to be stored in the memory.

Accordingly, it is rendered possible to send and receive digital data between mobile phones in one another's vicinity, without the need for dedicated short range RF transceivers or RF transceivers .

The modulation and the demodulation are preferably performed in a Digital Signal Processor (DSP) unit that also handles the D/A and A/D conversion of audio signals to the loudspeaker and from the microphone respectively. Since each mobile phone is provided with a DSP unit the modulator and demodulator can be implemented very cost effectively.

The modulator and demodulator are preferably a software implemented emulation of a Bell 103M or 212A, an ITU V.21, V.22, V.22bis, or V.23 modem.

It is yet another object of the present invention to provide a method of dialing a phone number stored in a mobile phone on a landline phone. This object is achieved in accordance with claim 20, by providing a method of dialing a number on a fixed network phone that is connected to the public switched network, comprising the steps of lifting the receiver of the fixed network phone, providing a mobile phone with at least one telephone number stored therein, placing the loudspeaker of the mobile phone in close proximity to the microphone of the fixed network phone, and playing the at least one phone number as a DTMF tone sequence over the loudspeaker of the mobile phone to thereby dial the number on the fixed network phone . It is yet another object of the present invention to provide a mobile phone that is capable of dialing a number on a landline phone. This object is achieved in accordance with claim 21, by providing a mobile phone comprising a microprocessor, a memory device and a loudspeaker, a phone book application for storing telephone numbers in the memory device, a dialer application for allowing a user to select a number stored in the phone book and to play the selected phone number as a sequence of DTMF tones over the loudspeaker without the mobile phone attempting to establish a connection to the phone number concerned via the mobile network.

The mobile phone preferably comprises a user interface with a keypad and a display, wherein the dialer application allows the user to select a phone number from the phone book for playing it as DTMF tones over the loudspeaker via interaction with the user interface.

Further objects, features, advantages and properties of the method of transmitting data, and the mobile phone according to the invention will become apparent from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiments shown in the drawings, in which:

Fig. 1 illustrates an embodiment of a mobile phone in accordance with the present invention,

Fig. 2 is a block diagram illustrating the general architecture of the mobile terminal of Fig. 1, Fig. 3 illustrates two mobile phones placed within audible range from one another for sonic data transmission,

Fig. 4 illustrates the active components in a block diagram of two mobile phones in a sonic data transmission,

Figs. 5.1 to 5.7 illustrate the menu items shown on the display for initiating a sonic transmission,

Figs. 6.1 to 6.5 illustrate the menu items shown on the display for activating sonic data reception, and

Fig. 7 is a table illustrating the conversion of ASCII characters to DTMF tones .

DETAILED DESCRIPTION

In the following detailed portion of the present description, the invention will be explained in more detail with reference to the' exemplary embodiments shown in the drawings, in which Fig. 1 shows a mobile phone 1 for use with the present invention.

The mobile phone, comprises a user interface having a keypad 2, a display 3, an on/off button (not visible, present in the top of the phone) a speaker 5 (only the opening is visible) , and a microphone 6 (only the opening present in the bottom of the phone is visible) . The mobile phone 1 according to the preferred embodiment is adapted for communication via a cellular network, such as the GSM 900/1800 MHz network, but could just as well be adapted for use with a Code Division Multiple Access (CDMA) network or a G3 network.

According to a preferred embodiment, the keypad 2 has a first group 8 of keys as alphanumeric keys, two softkeys 9, a cursor navigation key 10 (scroll up/down/left/right), and on-hook and off-hook keys 12. The present functionality of the softkeys 9 is shown in separate fields 21 (softkey-labels) in the display 3 just above the softkeys 9. The softkeys 9 are multifunction keys and their present function depends on the state of the mobile phone 1. The softkeys 9 give access to the menu, the phonebook and can activate actions related to call handling and message handling.

FIG. 2 illustrates in block diagram form the general architecture of the mobile phone constructed in accordance with the present invention. The mobile phone includes a microprocessor 18 for controlling the operation of the mobile phone, a program memory (flash ROM 17b) for storing programs used by the mobile telephone and a random access memory (RAM 17a) . Input/output circuits interface the microprocessor 18 with a keypad 2, a display 3, digital signal processing unit 14, and the receiver/transmitter circuit 19. The receiver/transmitter circuit 19 is connected to an internal antenna 15. The digital signal processing circuit 14 provides analog audio outputs to the speaker 5 and accepts analog audio inputs from the microphone 6. The processor 18 also forms the interface to the peripheral units of the apparatus, including the SIM card 16, as well as power supply, etc.

Fig. 3 illustrates a first mobile phone 1 and a second mobile phone 1' that are placed within audible range from one another. For acoustic/sonic data transmission the effective range depends on the amount of ambient noise and on the presence of sound dampening obstacles between the mobile phones . With low ambient noise levels an no sound dampening obstacles the effective range is up to 2 meter . Preferably, the mobile phones 1 and 1' are placed face to face (not shown) , with the phones oriented upside down relative to one another so that the loudspeakers face the microphones and a minimum air gap there between is obtained. This way of arranging the mobile phones is particularly useful in noisy environments.

Fig. 4 illustrates the active components of the two phones during the sonic communication. The digital data to be sent from mobile phone 1 to mobile phone 1' is retrieved from the RAM 17a or Flash ROM 17b (alternatively data such as phone book entries can be retrieved from the SIM card 16) by the processor unit 18 and passed on to the DSP unit 14a. The DSP unit 14a produces a pilot audio sequence to activate sonic reception in any other mobile phones in the vicinity. The sequence is converted from a digital signal to an electrical one by the D/A digital to analog converter 14b and turned into sound by the loudspeaker 5.

Then the DSP unit 14a converts the data for transmission into a modulated digital audio sequence. The method of modulation can be frequency shift keying (FSK) , amplitude modulation, frequency modulation, differential phase modulation, phase shift keying (PSK) , quadrature amplitude modulation (QAM) or orthogonal frequency division multiplexing (OFDM) . The modulated data is converted from a digital sequence to an analog electrical signal by the D/A digital to analog converter 14b and made into sound by the loudspeaker 5. The frequency spectrum of the sonic signal lies within the human audible range, preferably in the speech band, for which the in-built loudspeaker and microphone are optimized in advance . In a preferred embodiment the modulator is programmed to operate in accordance with a Bell or ITU modem recommendation, e.g. ITU recommendation V.21, "300 Bits Per Second Duplex Modem Standard for use in the General Switched Telephone Network" , hereby incorporated by reference. The modulator is integrated in the DSP unit 14. The modulation is a binary modulation obtained by frequency shift, resulting in a modulation rate being equal to the data signaling rate. The maximum power output of the modulator may exceed the recommendation of the V.21 standard, e.g. when transmission is difficult because of a relatively great distance between the mobile phones to ensure an adequate loudness of the sonic signal. Alternatively any other ITU recommendation such as V.22, V.22bis, V.23 or any other ITU recommendation with a higher bit transfer rate can be used.

The sonic reception in receiving phones can be activated by a pilot tone, or the sonic reception can always be active. A wake up module 20,20' receives signals from the microphone 6,6' and has an output connected to the processor 18,18' to provide a trigger to wake up the processor if it is in sleep mode.

The power level of the signal to the loudspeaker 5 is adjusted for loss lever in the sonic transmission from the loudspeaker 5 to the microphone 6' . The adjustment can be automatic or manual. Manual adjustment can be particularly useful for reducing noise pollution in situations where the circumstances for sonic transmission are optimal, (e.g. a short range in a quite place) . The sonic signal is picked up by the microphone 6' of the second mobile phone 1' . The signal from the microphone 6' is fed to a A/D converting part of the DSP unit 14' that forms a demodulator . The demodulator converts the analogue signal back into digital data. The digital data is transferred via the processor unit 18' to the RAM 17a' . The demodulator can operate with the same modulation methods as the modulator of the sending modulator. Both mobile phones comprise a modulator and demodulator. Thus each phone comprises a modem for sonic transmission, the sending phone an originating modem and the receiving phone an answer modem.

The fastest transmission speed that can be handled by the modems of both mobile phones is negotiated during the handshaking sequence . The modems can test the sonic transmission quality and fall back to slower speeds if the sonic transmission cannot handle the modem's fastest speed.

A according to an embodiment, the sonic signal is protected by error correction, preferably by a parity check, Reed-Solomon error correction codes and/or Viterbi coding.

The data to be transferred does not need to originate from the phone memory, it can also originate from keypad inputs .

The access method to the sonic signal can be various, i.e. point to point or point to multi point. The first mobile phone to send a sonic signal is the master unit, whereas any other units that connect after the sending of the initial sonic signal are slave units. More sophisticated multipoint protocols, such as e.g. known from the Bluetooth standard can also be used.

For privacy and security reasons the data can be encrypted using a public key and a non-public key pair. For extremely noisy environments the modems can fall back on Dual Tone Multi Frequency (DTMF) tone sequences for modulation because the DTMF tones are designed for robustness in a high noise environment. The DTMF tone generation is preferably hardware based in an integrated circuit.

The data that can be send with the sonic signal comprises phone book entries, color pictures, ringing, tones and other user data that is typically stored on a mobile phone. Also commands to control the receiving phone can be sent as sonic signals, e.g. commands to activate the camera in a receiving phone equipped therewith. The command could be sent for making a snapshot or for activating a motion video recording. The DSP 14 in the receiving phone is hereto programmed to recognize received commands from user data, and sends the commands to the processor unit 18 for execution.

Because the originate and answer modems transmit different tones, they can operate simultaneously, i.e. it is possible to use full-duplex operation.

The sensitive or the receiving mobile phone is can be equalized to reject noise outside the reception band.

The encoding does not necessarily have to follow a existing modem recommendation. A transmission mode according to an embodiment of the present invention transmits the ASCII sign table by a sequence of DFTM tones in accordance with the table shown in Fig.7. The transmission has a 2-bit format followed by a stop bit. This transmission format can be used to text, but also for the transmission of single a character. The latter being useful for wakeup, upper/lower case selection, code table selection, identification, synchronization and authentication.

Alternatively, a sequence of key stokes that was used to create a text, e.g. an SMS, in the form of a sequence of the DTMF tones in the format in which DTMF tones are assigned to the 12 standard keys of the phone keypad. The receiving phone converts the received DTMF tones to keystrokes and converts the keystrokes to text. Hereto, the sending phone preferably includes a header informing if the keying format is multitap or predictive editing / language use for predictive editing. Alternatively the receiving phone is provided with an algorithm that can deduct from a received DTMF sequence in which way the text has been entered, using e.g. in-built language dictionaries. For the transmission of multitapped texts the sending phone preferably adds an end of character DTMF tone after each character to avoid having to include delays in the signal that represent the timeout period used in multitapping. When sending numbers in a text created with predictive editing the sending phone adds a "number" DTMF tone after the character concerned to inform the receiving phone that the last received character is not a letter that forms part of a word. The mode of sending can be mixed, to send texts that have been created by a mixture of predictive editing and multitapping .

For communication between mobile phones during gaming applications the single transmission of the standard DTMF tones associated with the 1,2,3,4,5,6,7,8,9,0,* and # keys of the keypad can be used to play a game "online" with two or more players . The single DTMF tone created by the activation of a key of the phone of one of the players is automatically followed by a player identification tone. The DTMF tones are assigned to the keypad equivalents "A","B","C" and "D" , keys that are normally not present on mobile phones, are used to identify up to four players in a game. At the game setup one of the four DTMF tomes associated with the keypad equivalents A,B,C,D is allocated to the two to four players of the game.

More sophisticated sonic communication methods in "online" gameplay based on the table of Fig. 7 can of course be applied.

Figs. 5.1 to 5.7 illustrate the procedure for sending a phone book entry. In the idle mode the display 3 shows the operator logo 21 in the center of the display and the soft labels 22 of the softkeys 9 in a dedicated area at the bottom of the display 3. The left softkey 9 gives access to the menu structure, the right softkey gives access to the phone book.

After pressing the right softkey 9 the display lists the menu items that are associated with the phone book (Fig. 5.2). The first menu item is automatically highlighted and the user can use the up-down part of the navigation key 10 to move backward and forwards in the list. The left softkey label 22 has changed to "Select" and the right softkey label 22 has changed to "Exit" . By using the navigation key 10 "down" four times the menu item "Options" is highlighted.

After pressing the left softkey 9 "Select" the items in the submenu "Options" are listed (Fig. 5.3) . By using the navigation key 10 "down" three times the submenu item "Send number" is highlighted.

After pressing the left softkey 9 "Select" the text "Send number with sonic signal?" is shown in the display 3 (Fig 5.4). The left softkey label 22 has changed to "Yes" and the right softkey label 22 has changed to "Back" .

After pressing the left softkey 9 "Yes" the display lists the phone book entries that are stored in the mobile phone 1 (Fig. 5.5). By using the navigation key the user highlights the phone book entry to be send and selects the highlighted entry by pressing the left softkey 9 "Select" .

The data concerning the selected phone book entry is then transferred from the SIM card 16 or from the Flash ROM 17b to the modulator in the DSP unit 14. The modulator coverts the data into an analogue signal that drives the loudspeaker 5 to thereby produce a sonic data signal.

For the sonic data signal to be picked up a second mobile phone has to be within audible range and the sonic reception of the second mobile phone must be activated. The reception can be activated by a DTMF tone sequence produced by the first mobile phone, or by the user of the second phone, through the user interface.

Figs. 6.1 to 6.5 illustrate the procedure for activating the reception of sonic data. In the idle mode (Fig. 6.1) the user presses the left softkey 9 "Menu" . The display then lists the menu items (Fig. 6.2). The left softkey label changes to "Select" and the right softkey label changes to "Exit" . By pressing the navigation key 10 "down" three times the menu item "Connectivity" is highlighted.

Subsequent activation of the left softkey "Select" causes the display to list the "Connectivity" submenu items "Sonic" and "GPRS" (Fig 6.3) . The submenu item "Sonic" is listed first and therefore automatically highlighted. The sonic reception is activated after the left softkey "Select" has been pressed. The display shows the text "Sonic reception activated" and the phone returns to the idle mode with the sonic reception activated, shown by the sound wave icon 25 in the upper left corner of the display 3 (Fig. 6.5).

The mobile phone is now ready for receiving a sonic data signal from another mobile phone. If no sonic data signal is received within a predetermined period (e.g. two minutes) the sonic reception is automatically deactivated.

According to another embodiment of the present invention the mobile phone can be used to dial a number on a fixed network phone (not shown) that is connected to the public switched network. The mobile phone is provided with a phone book application for storing telephone numbers on the SIM card 16 or the RAM 17a. The phone further comprises a dialer application that allows a user to select a number stored in the phone book for playing the selected phone number as a sequence of DTMF tones over the loudspeaker 5 without the mobile phone attempting to establish a connection to the phone number concerned via the mobile network. The selection of the phone number and the activation of the DTMF tone sequence is performed with the above described user interface, that allows the user to search the phone book and play the DTMF tone sequence over the loudspeaker 5 without the mobile phone itself dialing the number.

After selecting the phone number to be dialed, the user lifts the receiver of the fixed network phone and places the mobile phone on the receiver with the loudspeaker 5 facing the microphone in the receiver. Then, the user activates the function of playing the selected phone number as DTMF tones over the loudspeaker 5. The DTMF tone sequence is picked up by the microphone and transmitted to the telephone central which in turn establishes a connection to the phone number concerned.

Although the present invention has been described in detail for purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the scope of the invention.

Thus, while the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. Other embodiments and configurations may be devised without departing from the scope of the appended claims.

Claims

CLAIMS :

1. A method of transmitting digital data from a first mobile phone having an in-built microphone and loudspeaker to a second mobile phone having an in-built microphone and loudspeaker, comprising steps of: placing the first and second mobile phone within audible range from one another,

- the first mobile phone modulating digital data into an analogue signal that is fed to the in-built loudspeaker to produce a sonic signal,

- the second mobile phone picking up said sonic signal with the in-built microphone and demodulating the sonic data signal into digital data.

2. A method according to claim 1, wherein the distance between the mobile phones is in the range of 0,1 cm to 2 meter without any sound dampening obstacles there between.

3. A method according to claim 1 or 2, wherein the sonic signal is a narrow band signal that lies within the human audible range, preferably in the voice band range.

4. A method according to any of claims 1 to 3, wherein the first mobile phone modulates digital data stored in a memory of the first mobile phone

5. A method according to any of claims 1 to 4, wherein the second mobile phone stores the received data in a memory of the second mobile phone.

6. A method according to any of claims 1 to 5, further comprising the step of the first mobile phone sending a pilot tone for synchronizing the transmission, preferably a pilot tone that comprises sequence of DTMF tones.

7. A method according to any of claims 1 to 6, wherein DTMF tone sequences are used in the sonic signal.

8. A method according to any of claims 1 to 7, wherein frequency shift keying is used to modulate the data.

9. A method according to any of claims 1 to 8 , wherein amplitude modulation is used to modulate the data.

10. A method according to any of claims 1 to 9, wherein frequency modulation is used to modulate the data.

11. A method according to any of claims 1 to 10, wherein phase modulation, preferably differential phase modulation is used to modulate the data.

12. A method according to any of claims 1 to 11, wherein phase-shift keying is used to modulate the data.

13. A method according to any of claims 1 to 12, wherein quadrature amplitude modulation is used to modulate the data into a sonic signal.

14. A method according to any of claims 1 to 13, wherein error correction is applied, preferably by a parity check, Reed-Solomon error correction codes and/or Viterbi coding .

15. A method according to any of claims 1 to 14 , wherein the data modulated encoded in accordance with an analogue modem standard, preferably in accordance with the Bell 103M or 212A standard, the ITU V.21, V.22, V.22bis, or V.23 recommendation.

16. A method according to any of claims 1 to 15, wherein the sonic signal is encrypted for private point to point data transmission using a combination of a private key and a public key.

17. A mobile phone comprising: an in-built microphone, an in-built loudspeaker, a processor unit, a memory interfacing with the processor unit, a modulator interfacing with the processor unit and with the in-built loudspeaker, the modulator being capable of converting digital data stored in the memory into signal for the in-built loudspeaker to produce a sonic data carrying signal, a demodulator interfacing with the processor unit and with the in-built microphone, the demodulator being capable of converting a sonic data carrying signal picked up by the in-built microphone into digital data to be stored in the memory.

18. A mobile phone according to claim 17, wherein the modulation and the demodulation are performed in a digital signal processor that also handles the D/A and A/D conversion of audio signals to the loudspeaker and from the microphone respectively.

19. A mobile phone according to claim 17 or 18, wherein the modulator and demodulator are a software implemented emulation of a Bell 103M or 212A, an ITU V.21, V.22, V.22bis, or V.23 modem.

20. A method of dialing a number on a fixed network phone that is connected to the public switched network, comprising the steps of: lifting the receiver of the fixed network phone providing a mobile phone with at least one telephone number stored therein; placing the loudspeaker of the mobile phone in close proximity to the microphone of the fixed network phone; and playing the at least one phone number as a DTMF tone sequence over the loudspeaker of the mobile phone to thereby dial the number on the fixed network phone.

21. A mobile phone comprising: a microprocessor, a memory device and a loudspeaker; a phone book application for storing telephone numbers in the memory device; a dialer application for allowing a user to select a number stored in the phone book and to play the selected phone number as a sequence of DTMF tones over the loudspeaker without the mobile phone attempting to establish a connection to the phone number concerned via the mobile network.

22. A mobile phone according to claim 21, further comprising a user interface with a keypad and a display, wherein the dialer application allows the user to select a phone number from the phone book for playing it as DTMF tones over the loudspeaker via interaction with the user interface.