DETAILED DESCRIPTION OF EMBODIMENTS

[0036] FIG. 1 shows a survey of a telephony system TS 1 with an embodiment of the invention. A first mobile radio telephone M 1 , having a phone number Ph 1 , is connected to a first mobile radio telephony network MTN 1 via a radio link R 1 to a radio base station BS 1 . This station belongs to the first mobile telephony network. A subscriber telephone S 2 is connected to a public telephony network PSTN 1 , which in turn is connected to the mobile telephony network MTN 1 . The mobile telephone M 1 communicates with an inventive stationary telephony terminal S 1 via a short range wireless link SWL 1 . In the present embodiment the wireless link SWL 1 is a short range bluetooth radio link between bluetooth transceivers, of which a first transceiver BT 1 is connected to the mobile telephone M 1 and a second transceiver BT 2 is connected to the stationary telephony terminal S 1 . A second mobile radio telephone M 3 , owned by a subscriber P 3 , is within the area of the first mobile radio telephony network MTN 1 . A second mobile radio telephony network MTN 2 has a second radio base station BS 2 , which is connected to the public telephony network PSTN. A second stationary telephony terminal S 3 , which is placed on a complete different location than the stationary terminal S 1 , is within a cell covered by the base station BS 2 and has a bluetooth transceiver BT 3 .

[0037] In FIG. 1 , for the sake of simplicity, the mobile telephony network MTN 1 is shown with the only base station BS 1 . The network is a common mobile network with several base stations, mobile switching centres, gateways and the like, not shown in the figure.

[0038] The stationary terminal S 1 has similarities with a conventional stationary deskphone in that it has a telephone body 1 , a handset 2 and is provided with a keyset 3 and a display 4 . As an alternative to the keyset 3 it also has a device 3 a for voice command. The terminal S 1 differs from the conventional deskphone in that it lacks a wire for connection to a telephony network but has only a power cord 5 connected to a conventional power socket. The stationary terminal S 1 also differs from the conventional deskphone in that it has the abovementioned bluetooth transceiver BT 2 and in that it lacks an own telephone number. The second stationary telephony terminal S 3 is similar to the terminal S 1 and functions in the same manner. The stationary terminal S 1 will be described more in detail below.

[0039] The bluetooth transmission is specified in the Bluetooth Specification 1.1. In short bluetooth works in the following manner. Bluetooth is a frequency hopping system with 79 frequencies within a band and with 1600 frequency hops per second. The hops follow a pseudo random hop sequence. Each bluetooth device has a 48-bit IEEE address determined by a manufacturer number and a consecutive number and the hop sequence for a bluetooth device is determined by applying an algorithm on the address. Each bluetooth device has an own clock time and if this time and the address is known it is possible to go directly into the hop sequence for a certain bluetooth device and follow it. The communication between bluetooth devices is organized with a master and one or more slaves forming a pico network, in which the hop sequence is determined by the master.

[0040] A bluetooth device can search another bluetooth device by making either a page or an inquiry. In case of page the address of the sought bluetooth device is known to the searching device and in case of inquiry the address is unknown and the sought bluetooth device can be any device. The bluetooth devices listen on 32 different frequencies, about one second for each frequency. A paging bluetooth device sends the address of the sought device, rapidly changing between all 32 frequencies, and will hit the sought device. An inquiring bluetooth device sends a certain code in stead of the address, rapidly changing frequency. A listening device that hears this code responds with its address and clock time. The entire bluetooth specification is to be found on the web under address www.bluetooth.com.

[0041] In brief the stationary terminal S 1 is used in the following manner. A subscriber P 1 , who owns the mobile telephone M 1 , visits a room with the stationary telephony terminal S 1 . The mobile M 1 has established contact with the mobile network MTN 1 via the link R 1 and is in its standby position. The subscriber P 1 wants to call the telephone S 2 and prefers to use the stationary terminal S 1 , because it has the keyset 3 that is big and easy to use, the display 4 that is big and easy to view and the convenient handset 2 . The subscriber lifts the handset 2 and keys the number to the telephone S 2 on the keypad 3 . A channel on the bluetooth link SWL 1 is set up to the mobile telephone M 1 , which initiates the mobile to switch to its active mode. A channel on the radio link R 1 between the base station BS 1 and the mobile telephone M 1 is set up and the telephone S 2 is then called via the mobile network MTN 1 and the public network PSTN 1 in conventional manner. A subscriber P 2 takes the call on the telephone S 2 and a conversation can take place.

[0042] When the subscriber P 2 wants to call the subscriber P 1 , he dials the number to the mobile telephone M 1 on his telephone S 2 . The call is coupled through the public network PSTN 1 and the mobile network MTN 1 to the base station BS 1 , through which a channel on the radio link R 1 is set up to the mobile telephone M 1 . The mobile telephone is initiated to call the stationary terminal S 1 via the short range link SWL 1 . The stationary deskphone generates a ringtone, the subscriber P 1 lifts the handset 2 and a conversation between the subscibers P 1 and P 2 can take place.

[0043] The subscriber M 1 can bring the mobile radio telephone M 1 along and move to the location for the second stationary telephony terminal S 3 . There telephony calls can be set up via the stationary terminal S 3 and also incoming calls to the mobile M 1 can be taken on the terminal S 3 in the same way as for the stationary terminal S 1 .

[0044] FIG. 2 is a block diagram showing the stationary telephony terminal S 1 . The latter has a processing unit 6 which is connected to the keyset 3 and the display 4 . The processing unit is also connected to an analog-digital converter 7 and to a unit 9 with a hook function. The analog-digital converter is connected to an amplifier 8 for a loudspeaker or microphone function and to the handset 2 , which actuates the hook function 9 . The bluetooth transceiver BT 2 is connected to the processing unit 6 and is also connected to the analog-digital converter 7 an has an antenna 10 for the short range link SWL 1 . The transceiver BT 2 has also a direct connection 11 a, past the processing unit 6 , for exchaning speech signals with the converter 7 . A bell 11 is connected to the processor 6 . The display 4 is a conventional one and is controled by the processing unit 6 . Telephone numbers are keyed on the keyset 3 , which also is used to key codes for programming the functions of the processor 6 , as will be discussed later. The unit 9 has a common hook function, which indicates hook-on or hook-off position of the handset 2 and actuates the processor 6 . The handset 2 is a common one with microphone and loudspeaker. Also the amplifier 8 is a common one for processing speech signals when the telephony terminal S 1 is set in a loudspeaking position. The converter 7 converts speech signals analog-to-digital and digital-to-analog in conventional manner. The Bluetooth transceiver BT 2 , having a bluetooth device address BE 2 , transmits and receives speech and signalling information on the link SWL 1 . When a telephone number is keyed on the keypad 3 , the number is processed in the processor 6 and corresponding signals are sent by the trasceiver BT 2 to the trasceiver BT 1 in the mobile telephone M 1 . Speech signals via e.g. the handset 2 are transceived by the transceiver BT 2 . For an incoming call to the mobile telephone M 1 and the stationary terminal S 1 the transceiver BT 2 receives a ring initiating signal, which initiates the processor to generate a ring signal on the bell 11 . In an alternative embodiment the stationary terminal is used so that it is the mobile that is ringing while the call still can be taken on the terminal.

[0045] FIG. 3 is a block diagram showing the mobile telephone M 1 . The mobile has a processing unit 16 which is connected to a keyset 13 and a display 14 . The processing unit 16 is also connected to an analog-digital converter 17 which in turn is connected to a microphone and a loudspeaker. A bell 21 is connected to the processing unit. The mobile phone also has a radio circuit unit 19 which is connected to the processing unit 16 and has an antenna 20 for the radio link R 1 . The bluetooth transceiver BT 1 is connected to the processing unit 16 and has an antenna 12 for the short range link SWL 1 . The transceiver BT 1 has a direct connection 22 to the converter 17 and a direct connection 23 to the radio unit 19 . The direct connections 22 and 23 are used for exchange of speech signals past the processing unit 16 . The processing unit 16 is loaded with software 15 . The display 14 is a conventional one and is controlled by the processing unit. The keyset 13 is also conventional and is used to key telephone numbers, control menus on the display etc. The radio circuit unit 19 transmits and receives radio signals in conventional manner and the analog-digital converter 17 converts speech signals, also in conventional manner. The bluetooth transceiver BT 1 transmits and receives speech and signalling information on the link SWL 1 . The processing unit 16 performs conventional operations in a mobile phone and the software 15 performs operations which are required in the present invention. The transceiver BT 1 has a bluetooth device address BE 1 and can be set in different modes by pressing buttons on the keyset. A first mode is e.g. for communication with a conventional bluetooth headset and a second mode is for communication with the transceiver BT 2 in the stationary telephony terminal S 1 . As an alternative mode a subscriber can talk and listen via the headset, but still keys numbers on the stationary terminal. When an incoming call comes to the mobile telephone M 1 and the transceiver BT 1 is in the second mode, the call is sent on to the transceiver BT 1 by the software 15 . Among others the ring initiating signal in the call is handled by the software 15 and is transmitted to the transceiver BT 1 instead of being transmitted to the bell 21 . A telephone number keyed on the keyset 3 on the stationary terminal S 1 is transmitted via the short range link SWL 1 to the transceiver BT 1 and to the processing unit 16 . With the aid of the software 15 the telephone number is transmitted from the mobile phone via the link R 1 as if it was keyed directly on the keyset 13 . In an alternative embodiment the ring initiating signal is transmitted to both the bell 21 and to the transceiver BT 1 and in still an alternative only to the bell 21 .

[0046] In connection with signalling diagrams in FIGS. 4 to 11 it will be described in closer detail how the stationary telephony terminal S 1 works and is used when communicating with the telephone S 2 .

Discovery Phase 1

[0047] FIG. 4 is a signalling diagram for the stationary telephony terminal S 1 , the mobile telephone M 1 and the base station BS 1 , in which diagram the time is denoted by T. The situation in connection with FIG. 4 is that the stationary telephony terminal S 1 stands in a room, is powered from a common power socket and is switched on. The terminal transmits repeatedly inquiry signals 31 by its bluetooth transceiver BT 2 over the bluetooth short range link SWL 1 . The terminal thereby requests for contact with other bluetooth devices. The subscriber P 1 comes into the room with the mobile telepone M 1 and switches it on at a moment 32 . Signals 33 are sent by the radio unit 19 on a signalling channel over the radio link R 1 between the mobile M 1 and the basestation BS 1 . The network MTN 1 recognizes the mobile M 1 and notes its geographical position. This is performed in a conventional manner and the mobile is in its standby mode. In an alternative the mobile M 1 is already switched on and has contact with the base station BS 1 when it comes in range of the bluetooth transceiver BT 2 at the moment 32 . The mobile receives the inquiry signals 31 via its bluetooth transceiver BT 1 . At a moment 34 the mobile M 1 sends inquiry response signals 35 a back to the stationary terminal S 1 on the channel 35 . The response signals 35 a includes the bluetooth address and the clock time for the terminal BT 1 , according to the bluetooth specifications. At a moment 36 the terminal S 1 receives the signals 35 a and a piconet with the transceiver BT 2 as master and the transceiver BT 1 in the mobile telephone as slave is set up with a page/page response sequence as described in the bluetooth specifications. This sequence is not shown in the figure. At a moment 37 the terminal BT 2 identifies itself as a stationary terminal with an identification signal. At a moment 38 the terminal BT 1 identifies itself as a mobile with an identification signal, which includes the mobile telephony number Ph 1 . The use of the stationary terminal S 1 requires in many cases an authentication as will be described in connection with FIG. 9 .

[0048] In an alternative embodiment the bluetooth terminal BT 2 directly pages the bluetooth terminal BT 1 , if the terminal BT 2 already has the bluetooth device address for the terminal BT 1 . When this terminal responds on the page the piconet is established. Also other mobile telephones with bluetooth transceivers can be connected as slaves in the piconet with the transceiver BT 2 as master. If the mobiletelephone M 1 with the transceiver BT 1 moves out of range from the stationary terminal S 1 with the transceiver BT 2 so that the piconet connection is lost, when it returns the piconet will again be restored as described above.

Incoming Call to the Stationary Telephony Terminal S 1

[0049] FIG. 5 is a signalling diagram for the setting up of a call from the telephone S 2 in the public network PSTN 1 to the mobile telepone M 1 , when the mobile subscriber P 1 selects to take the call on the stationary telephony terminal S 1 . The discovery phase is already completed as described above.

[0050] The subscriber P 2 dials at a moment 40 the telephony number to the mobile telephone M 1 on the telephone S 2 . The call is coupled through the networks PSTN 1 and MTN 1 in conventional manner to the base station BS 1 , denoted by reference 41 . The mobile telephone is called, denoted by reference 42 , via the base station on a signalling channel over the radio link R 1 by a message “Incoming call”. At a moment 43 the mobile notes the incoming call from the telephone S 2 . By signalling 44 a speech channel between the base station BS 1 and the mobile telephone M 1 is allocated in is conventional manner. The mobile M 1 is a slave in the pico network with the terminal S 1 as master. It thus transmits the message “Incoming call” on the already established bluetooth channel to the terminal S 1 with the aid of the software 15 . This transmission comprises in the present embodiment the telephony number of the the calling telephone S 2 and is denoted by reference 45 . A ring signal is generated in the mobile M 1 , the subscriber P 1 lifts the handset 2 of the stationary terminal and the hook function 9 is activated, which is all denoted by reference 46 . A response signal is sent to the mobile, indicating that the stationary telephony terminal S 1 will answer the call (off-hook), and including an authentication code that the subscriber has keyed earlier, all denoted by reference 47 , and a speech channel over the bluetooth link SWL 1 is set up. The mobile M 1 also receives the off-hook message at a moment 48 . The off hook message initiates the mobile M 1 to send a message with the aid of the software 15 to the mobile network MTN 1 via the base station BS 1 , denoted by reference 49 . This message correspond to the messege which is sent when the subscriber P 1 takes a call directly on the mobile M 1 by pressing the “Answer” button. The earlier designated speech channel to the base station is set up at a moment 50 and a conversation can take place.

Call Released from the Stationary Telephony Terminal S 1

[0051] FIG. 6 is a signalling diagram for the release of the call by the stationary telephony terminal S 1 .

[0052] The subscriber P 1 replaces the handset 2 at a moment 52 and the hook function 9 is deactivated. As denoted by reference 53 the mobile telephone M 1 is informed of this fact via a signalling channel over the bluetooth link SWL 1 . The software 15 activates the mobile telephone to signal the call release to the network over a signalling channel on the link R 1 , referenced by 54 . This is performed in the same way as if a corresponding release button on the keyset 13 of the mobile was pressed. The channel through the networks MTN 1 and PSTN is released, which is denoted by reference 55 , and the speech channel over the Bluetooth link SWL 1 is released, denoted by reference 56 .

Call Released from the Telephone S 2

[0053] FIG. 7 is a signalling diagram for the release of the call by the telephone S 2 in the public network PSTN 1 .

[0054] The subscriber P 2 goes on-hook at a moment 71 , which is signalled through the networks PSTN 1 and MTN 1 as denoted by the reference 72 . The base station BS 1 signals the call release to the mobile M 1 as denoted by the reference 73 . The processing unit with the software 15 is activated and sends a release signal to the stationary telephony terminal S 1 , denoted by reference 74 . The connection between the stationary telephony terminal S 1 and the telephone S 2 is released in a conventional manner. At a moment 75 the subscriber P 1 goes on-hook.

Outgoing Call from the Stationary Telephony Terminal S 1

[0055] FIG. 8 is a signalling diagram for the setting up of a call from the stationary telephony terminal S 1 to the telephone S 2 in the public network PSTN 1 via the mobile telepone M 1 . The discovery phase is already completed and the bluetooth piconet is established as described above.

[0056] The subscriber P 1 lifts the handset 2 at a moment 60 and the hook function 9 is activated. The subscriber keys the telephone number to the called subscriber telephone S 2 and presses a “yes” button when the number is completed. A bluetooth speech channel 61 is set up. As mentioned the subscriber P 1 has earlier keyed and stored an authentication code, which is now transmitted on the short range link SWL 1 to the mobile telephone M 1 . The authentication is accepted by the mobile M 1 as denoted by reference 62 . The button pressings in the dialled number are transmitted to the mobile telephone M 1 , which transmission is denoted by reference 63 . In an alternative the transmissions 61 and 63 are combined into one. The software 15 is activated by the transmitted button pressings and influences the processing unit 16 in the same way as if the the telephone number was keyed by the buttons on the key pad 13 of the mobile telephone M 1 . This is denoted by reference 64 . A signalling channel is set up between the mobile M 1 and the base station BS 1 , referenced 65 , and in a conventional manner a speech channel is allocated. The connection is set up through the networks MTN 1 and PSTN 1 , as denoted by reference 66 , and on a ring signal the subscriber P 2 lifts his handset on the telephone S 2 , denoted by reference 67 . This lifting is transmitted back to the base station BS 1 , denoted by reference 68 , and the earlier allocated speech channel is set up, which is denoted by reference 69 . A conversation between the subscribers P 1 and P 2 can take place.

[0057] In the above examples it is mentioned that the subscriber P 1 has his mobile radio telphone M 1 on, the bluetooth transceivers BT 1 and BT 2 are within range of each other, the mobile M 1 has identified itself to the stationary terminal S 1 , and the subscriber P 1 has to key an authentication code on the stationary terminal S 1 , that the terminal S 1 will send to the mobile M 1 . The subscriber then can key a telephone number on the stationary telephony terminal S 1 to reach the called subscriber or take an incoming call. Authentication is desirable in many situations because the subscriber P 3 in FIG. 1 can come into the room and bring an own mobile telephone M 3 with him, that is in standby position. When a call is keyed on the stationary terminal S 1 the question arises whose mobile telephone is to be used. Also, a person can on the sly place a stationary telephony terminal near to a mobile telephone and without permission try to make outgoing calls and take incoming calls on that mobile telephone. This is prevented by the authentication. It should anyhow be noted that in some cases the authentication is unnecessary, e.g. if the mobile phone is used in environments where only trusted persons or devices are within bluetooth range,or if the functionality for connecting to stationary deskphones as described here is turned off when the mobile phone is used in non trusted environments.

[0058] It has been mentioned above that setting up and taking a call on the stationary terminal S 1 can involve an authentication. To facilitate the use of the stationary terminals a relation between the stationary terminal and the mobile telephone can be defined with the aid of a code as will be described below in connection with FIGS. 9 and 11 .

Use of Service Code 1

[0059] FIG. 9 is a signalling diagram for an identification and authentication procedure between the mobile telephone M 1 and the stationary telephony terminal S 1 . As in FIG. 4 , the stationary terminal S 1 transmits the inquiry signals 31 , announcing itself. At a moment 81 the mobile telephone M 1 is switched on and begins to interchange signals 82 with the base station BS 1 in a conventional manner. The mobile telephone M 1 is programmed, via the software 15 , to identify itself before the stationary terminal S 1 not only as a mobile telephone but as an individual one. At a moment 83 the bluetooth terminal BT 1 of the mobile radio telephone M 1 receives the signal 31 , the piconet is set up as earlier described and the bluetooth address BE 1 and clock time for the bluetooth terminal BT 1 is transmitted according to the bluetooth specification. With the aid of the software 15 the terminal BT 1 automatically transmits its telephone number Ph 1 = 23397 with an identification signal 84 . At a moment 85 the stationary terminal S 1 receives, via the transceiver BT 2 , the signal 84 . It now has safely the information that the Bluetooth trasceiver BT 1 , with the identity BE 1 , represents the individual mobile radio telephone M 1 with the telephone number Ph 1 = 23397 . This information is stored. Note that stationary terminal S 1 not yet can be used for a call via the mobile telephone M 1 . Other mobile telephones, e.g. the mobile telephone M 3 , can move near to the stationary telephony terminal S 1 and identify themselves in the same manner.

[0060] The subscriber P 1 , owner of the mobile M 1 , now has to key a code on the stationary telephony terminal S 1 to set this terminal in a mode for communicating with the mobile telephone M 1 .

[0061] First a service code 91 , 92 or 93 is to be keyed, indicating how long a time interval for the communication mode will be. Then the telephone number 23397 of the mobile radio telephone M 1 has to be keyed and at last, for authentication, the PIN-code 1234 of the mobile phone M 1 is keyed. Thus the total code * 9 _ 23397 * 1234 # is keyed at a moment 86 , where 9 _ denotes any of the service codes. The keyed information is stored in the stationary telephony terminal S 1 . A relation between the mobile telephone M 1 and the stationary telephony terminal is now established. Provided that the entered PIN code is correct, outgoing calls can now be set up and incoming calls can be taken on the stationary telephony terminal S 1 . From the telephone number 93397 , the stationary telephony terminal S 1 knows the corresponding bluetooth address BE 1 of the mobile telephone M 1 to which messages should be sent, and by providing the PIN code, the stationary telephony terminal S 1 shows to the mobile telephone M 1 that it is authorised to communicate via the mobile telephone M 1 .

[0062] The PIN code is not sent from the stationary telephony terminal S 1 to the mobile telephone M 1 until a call is actually to be made or answered on the stationary telephony terminal S 1 .

[0063] In an alternative, when the PIN code 1234 has been entered it is transmitted in a message 87 to the mobile telephone M 1 . The mobile telephone M 1 receives the message at a moment 88 and checks the PIN code for correctness in the time interval 89 . At a moment 90 the mobile telephone M 1 sends a reply message 95 to the stationary telephony terminal S 1 , indicating if the PIN code was correct or not. The stationary telephony terminal S 1 receives the message and can indicate the result to the user by an audiable message or a message on the display.

[0064] When the stationary telephony terminal S 1 receives an “incoming call” message from another mobile telephone, e.g. the mobile telephone M 3 , it will find out by checking the previously stored information, that the telephone number Ph 3 that corresponds to the bluetooth device address of M 3 , is not the number Ph 1 of the mobile telephone M 1 , with which the stationary telephony terminal S 1 currently has a relation. Therefore, the terminal S 1 will not sound a ring signal.

[0065] As mentioned in the example above the service code 91 , 92 or 93 has to be keyed. In the example the service code is denoted by 9 _ to cover all situations. The service code is given the following meaning in the present example:

[0066] Code 93 is permanent and is intended to be used by e.g. the subscriber P 1 having the stationary telephony terminal on his ordinary desk. Once the subscriber has keyed the code * 9323397 * 1234 #, he needs not to key it again. He needs only to have his mobile telephone M 1 on, key a telephone number to a called subscriber on the stationary terminal S 1 or directly take an incoming call on the stationary terminal S 1 . This situation will endure for as long time as the subscriber decides.

[0067] Code 92 is to be used in the same way as code 93 , with the exception that it will only endure for a limited time interval. This interval can be e.g. one day or for as long time as the mobile telephone is in range of the short range transceiver BT 2 .

[0068] Code 91 is intended to be used for one call only. The subscriber P 3 with the mobile telephone M 3 in standby position comes into the room in which the stationary telephony terminal S 1 is located, see FIG. 1 . The mobile telephone M 3 has a number 23399 . When the subscriber P 3 wants to make a call on the stationary terminal S 1 , he first has to key his code * 9123399 * 4321 # on the stationary telephony terminal S 1 and can then make the call. When the call is finished the code will be deleted. If a call comes to the mobile telephone M 3 and the subscriber P 3 wants to take the call on the stationary telephony terminal S 1 , the subscriber has to first key his code * 9123399 * 4321 #.

[0069] The processor 6 in the stationary terminal S 1 can be programmed such that a lower-number service code overrides a higher number, but when the session or the call with the overriding service code ends, the previous service code is restored. This means that a subscriber, having the stationary terminal in his office, can key the service code 93 and always have access to the terminal when in office. Still someone else can use the stationary terminal for a call by keying the service code 91 . The stationary terminal can also be conveniently used by a person visiting the office for a few hours by keying the service code 92 . When this person leaves the office the stationary telephony terminal goes back to the original subscriber. Many persons can be in a room with a stationary telephony terminal and have their mobile radio telephones in standby mode. When a mobile telephone rings the person can immediately take the call on the stationary terminal by using the service code 91 .

[0070] In the above embodiment it is the telephone number Ph 1 of the mobile radio telephone M 1 that is the identification code. As an alternative to the telephone number Ph 1 the subscriber can select another own code.

[0071] The authentication number is, in the above embodiment, the PIN code of the mobile telephone M 1 . Also other authentication codes can be used that the subscriber selects.

[0072] The subscriber had to key the service code 9 _ in the above embodiment, before the called subscriber's telephone number was keyed. The service code, if any, can be performed in a number of different ways. It can e.g. comprise only two codes, one for permanent authentication and one for a single call. It can also have codes on top of the codes 91 , 92 and 93 , e.g. a code for a predetermined number of calls decided by the owner of stationary telephony terminal S 1 .

[0073] Also, in the above embodiment, the authentication was checked in the mobile telephone M 1 during the time interval 89 . Such a check can be transmitted from the mobile telephone M 1 over the link R 1 to the base station BS 1 . The authentication check is then performed in the land system of the mobile radio telephony network MTN 1 .

[0074] In the above embodiment the service code was given by pressing buttons 91 , 92 or 93 on the keypad of the stationary terminal S 1 . An alternative is that the terminal has a button designated for each of the codes or a corresponding menu driven interface.

[0075] In the above embodiments the stationary terminal S 1 sends the inquiry signal from the bluetooth transceiver to establish the pico network according to the bluetooth specification. If the bluetooth transceiver of the mobile telephone is known to the bluetooth transceiver of the stationary terminal, it can make a page which is somewhat faster than an inquiry.

Discovery Phase 2

[0076] FIG. 10 is a signalling diagram for the stationary telephony terminal S 1 , the mobile telephone M 1 and the base station BS 1 . The situation in connection with FIG. 10 is that the stationary telephony terminal S 1 stands in a room, is powered from a common power socket and is switched on. Compared with the situation in FIG. 4 , Discovery phase 1 , in FIG. 10 it is the mobile radio telephone M 1 that sends inquiry signals. The subscriber P 1 comes into the room with the mobile telepone M 1 and switches it on at a moment 101 . Signals 102 are sent by the radio unit 19 on a signalling channel over the radio link R 1 between the mobile telephone M 1 and the basestation BS 1 . The network MTN 1 recognizes the mobile telephone M 1 and notes its geographical position. This is made in a conventional manner and the mobile telephone is in its standby mode. At a moment 103 the mobile telephone begins to repeatedly send inquiry signals 104 by its bluetooth transceiver BT 1 on a channel 105 over the bluetooth short range link SWL 1 . The stationary telephony terminal S 1 receives the inquiry signals 104 via its bluetooth transceiver BT 2 and at a moment 106 it sends inquiry response signal 107 back to the mobile telephone M 1 . The response signal 107 includes the address and the clock time for the bluetooth terminal BT 2 . At a moment 108 the mobile radio telephone M 1 receives the signal 107 . A piconet with M 1 as master is then established through a page/page response sequence as described in the bluetooth specification (not shown). In an alternative, a master/slave switch is then performed so that the stationary telephony terminal S 1 becomes the master of the piconet.

Use of Service Code 2

[0077] FIG. 11 is a signalling diagram for an identification and authentication procedure between the mobile telephone M 1 and the stationary telephony terminal S 1 .

[0078] In this embodiment it is the mobile telephone M 1 that transmits the inquiry signal. At a moment 111 the mobile telephone M 1 is switched on and begins to interchange the signals 102 with the base station BS 1 in a conventional manner. The mobile telephone M 1 is programmed, via the software 15 , to identify itself before the stationary terminal S 1 not only as any mobile telephone but as an individual one. At a moment 112 the mobile radio telephone M 1 transmits the inquiry signal 113 . At a moment 115 the stationary terminal S 1 receives, via the transceiver BT 2 , the inquiry signal. At a moment 116 the stationary telephony terminal S 1 sends an inquiry response signal 117 back to the mobile radio telephone M 1 . A piconet with the mobile M 1 as master is then established through a page/page response sequence as described in the bluetooth specification (not shown). In an alternative, a master/slave switch is then performed so that the stationary telephony terminal S 1 becomes the master of the piconet. With the aid of the software 15 the mobile telephone also automatically transmits its telephone number Ph 1 = 23397 from the bluetooth transceiver BT 1 with an identification signal 118 . The terminal S 1 identifies itself as a stationary telephony terminal with an identification signal 119 . The terminal S 1 now safely has the information that the bluetooth transceiver BT 1 , with the identity BE 1 , represents the individual mobile radio telephone M 1 with the telephone number Ph 1 = 23397 . This information is stored. Other mobile telephones, e.g. the mobile telephone M 3 , can move near to the stationary telephony terminal S 1 and identify themselves in the same manner. The subscriber P 1 , owner of the mobile M 1 , now has to key the previous mentioned code on the stationary telephony terminal S 1 to set this terminal and the mobile telephone M 1 in a mode for communicating with each other. This communication is performed as described in connection with FIG. 9 and is not shown in FIG. 11 .

[0079] In connection with flow charts in FIGS. 12 to 15 the above described methods in connection with the stationary telephony terminal S 1 will be described in summary.

[0080] FIG. 12 shows a flow chart with the above “Discovery phase 1 ”. In a step 121 the stationary telephony terminal S 1 is powered on. Step 122 shows the transmitting of the inqury signals 31 from the stationary terminal S 1 . The mobile radio telephone M 1 is powered on in a step 123 and in a step 124 the mobile telephone is connected to the mobile radio telephony network MTN 1 . In a step 125 the mobile telephone M 1 receives the inquiry signal. As response the mobile telephone M 1 sends the inquiry response signal 35 a in a step 126 and a piconet is established in a step 127 . In a next step 128 the terminal S 1 identifies itself as a stationary telephony terminal and in a step 129 the mobile M 1 identifies itself as a mobile radio telephone.

[0081] FIG. 13 shows a flow chart with the above “Discovery phase 2 ”. In a step 131 the stationary telephony terminal S 1 is powered on and in a step 132 the mobile radio telephone M 1 is powered on. The mobile M 1 is connected to the mobile radio telephony network MTN 1 in a step 133 and in a step 134 the mobile transmits the inquiry signal 104 . The stationary terminal S 1 receives the inquiry signal 104 in a step 135 and in a step 136 it transmits the inquiry response signals 107 to the mobile telephone M 1 . A piconet is established in a step 137 . In a step 138 the mobile M 1 identifies itself as a mobile radio telephone with its number and in a step 139 the stationary terminal S 1 identifies itself as a stationary telephony terminal.

[0082] FIG. 14 shows a flow chart over a procedure use of service code when a call is made. It is presumed that the stationary telephony terminal S 1 is powered on and the mobile radio telephone M 1 is also powered on and is in contact with the mobile radio telephony network MTN 1 via the radio link R 1 . In a step 140 the stationary terminal S 1 transmits the inquiry signal 31 and in a step 141 the mobile radio telephone M 1 receives these inquiry signals. Trigged by the inquiry signal the mobile telephone M 1 transmits the inquiry response signal 84 with the bluetooth identity BE 1 in a step 142 . In a step 143 the piconet is set up and in a step 144 the telephone number Ph 1 = 23397 is transmitted to the stationary terminal S 1 . To be able to use the stationary terminal for a call the subscriber P 1 now keyes on the stationary terminal S 1 the service code 9 _ in a step 145 . In a step 146 the subscriber keyes the mobil's phone number Ph 1 = 23397 on the stationary terminal and in a step 147 the subscriber keyes the mobile's PIN code 1234 on the stationary terminal S 1 . The stationary terminal is now ready for use for as long time as the service code 9 _ permits. The subscriber P 1 keyes the number to the called subsriber S 2 and presses the “yes ” button in a step 148 . In a step 149 the keyed subscriber number and the total code * 9 _ 93397 * 1234 # is transmitted from the stationary terminal S 1 to the mobile telephone M 1 in a step 149 . In a step 150 it is checked that the PIN code is correct. This check can be performed in the mobile telephone M 1 or in the land system of the mobile network MTN 1 . If the code is wrong, an alternative “NO”, the call is rejected in a step 151 . If on the other hand the code is correct, an alternative “YES”, a bluetooth speech channel is set up on the link SWL 1 , step 152 . In a step 153 the mobile M 1 initiates a call to the telephone S 2 .

[0083] The above described embodiments of the invention can be further varied in a number of ways. An example is that the Bluetooth transceivers BT 1 and BT 2 can be replaced by optical IR transceivers. Another example is that the keying of telephone numbers on the keypad 3 can be replaced by voice commands, which are processed in the device 3 a.