WO1989000797A1

WO1989000797A1 - Motorcar telephone

Info

Publication number: WO1989000797A1
Application number: PCT/DE1988/000386
Authority: WO
Inventors: Alexander C. Hermesmeyer
Original assignee: Digatec Electronic Systems Gmbh
Priority date: 1987-07-17
Filing date: 1988-06-28
Publication date: 1989-01-26
Also published as: DE3723620A1; EP0377568A1

Abstract

A motorcar telephone comprises a radio apparatus (20) and an operating element (22) interconnected via at least one data line (24, 26) on the one hand and low-frequency lines (28, 30) on the other. To permit operation of an additional station, a switching unit (34) incorporated in the lines (24 to 30) - is connected with an additional apparatus, for example a cordless telephone, telefax machine, bell or similar, - has an interface (48) incorporated int he data line (24, 26) a data input (46, 64) of which is connected to one section of the data line (24, 26) and a data output (52) of which is connected to the other section of the data line (24, 26) via a (first) switch (54) at a linkage point (56), and - comprises a low-frequency switch (relay 66) controlled by said interface (48), which establishes a low-frequency connection between the radio apparatus (20) and the operating element (22) or the additional apparatus (26). A bypass line (50) -comprises a second switch (58) operating inversely to the first switch (54) - and is connected at one end to the data input (46) and at the other end to the linkage point (56).

Description

Name: car phone system

The invention relates to a car telephone system with a radio and an operating unit, which are connected on the one hand via at least one data line and on the other hand via LF lines.

In car telephone systems, the radio is typically located outside the passenger compartment, while the control unit is arranged, for example, between the two front seats or in the area of the dashboard. These two parts of the car telephone system are connected to one another via a multiple cable which comprises at least one data line and several, typically four LF lines. A handset, which is electrically connected to the control unit, is provided in the control unit or offset from the control unit.

If the car telephone system is switched on, both parts are initially supplied with voltage. This is followed by a data exchange between the radio and the control unit, which takes place in both directions. The car phone system is only ready for operation when this data exchange is complete and positive. The time period between switching on and operating state is referred to below as the "initialization phase". During this initialization phase, the radio searches for a free channel and makes contact with a radio concentrator. Depending on the local field strength conditions, the transmission power is sometimes increased or decreased. In the case of devices operating in the C network, the control unit, for example, asks whether the subscriber has inserted a subscriber card into the intended input slot. After completing the initialization phase, the car phone system is ready to send and receive. It can receive a call coming from outside via the Mobi radio telephone network or in turn send an R. However, this can only be done from within the vehicle or - b sufficiently long connecting cord of the handset to the operator - at the closest distance from the motor vehicle. If a car telephone subscriber has left his vehicle and is located near his motor vehicle, for example a doctor with a patient or a service technician with a machine or device, the person concerned cannot be reached via the car telephone. On the other hand, the person has no possibility of using the car phone that is in the immediate vicinity without going into the motor vehicle, for example, the doctor cannot call his practice via his own phone system, the service technician cannot speak to his company about his own car phone system .

In addition, the previously known car phone system of the type mentioned at the outset does not offer the possibility of installing additional extension devices, such as a fax machine or even a particularly loud phone bell. In other words, a car phone subscriber currently has to do without several technical options that are already state of the art for fixed-location systems. A private branch exchange for a car phone system, for example, is currently not available on the market. A loud alarm clock, as it is necessary for vehicles with their own high noise level, especially for sports vehicles, to hear incoming calls, is only possible with simple measures, such as detecting and amplifying the electrical or acoustic alarm signal, according to the prior art. possible. A real secondary alarm clock that works independently of the operator's alarm clock is currently not available.

This is where the invention begins. It has made it its task to insert an extension into the car phone system, which makes it possible, as an alternative to the control unit and handset, at least one auxiliary device, for example fax machine, answering machine, e operate a cordless telephone, an additional alarm clock or the like.

This object is achieved based on the car phone system of the type mentioned in that »for the operation of an extension, the lines between the radio and the control unit a Dmschalteinric device is inserted, with an extension device, for example a cordless phone, a fax machine, an alarm clock or The like is connected, which has an interface inserted into the data line, which is connected with its data input to one and its data output via a (first) switch in a connection point to the other part of the data line, and the NF-controlled by this interface. Ummschalter has a low-frequency connection from the radio either to the control unit or to the extension unit and that a bypass line is provided in which an inverse to the first switch operated second switch is inserted, which is connected at one end to the data input and at the other end to the connection point is t.

According to the invention, the switching device is thus inserted serially between the connection between the radio and the control unit. This means that no changes need to be made to these two parts themselves, rather the connection is made in the area of the connector between the control unit and the radio. The cable of the control panel is no longer plugged into the radio, but into the ummaltein direction, which in turn has a corresponding, multi-core cable for the plug connection with the radio. The invention thus enables the decisive advantage that interventions in the actual car telephone system, that is to say radio and control unit, are not necessary and that the switching device can be removed at any time without leaving any traces of it.

The bypass line and the two switches ensure that the changeover device is passi during the initialization phase. As a result, the data stream between the control unit and the radio as it occurs during the initialization phase is not disturbed and not affected either. The car telephone system therefore carries out the initialization as it would without the switching device according to the invention.

The bypass line with its two switches also has the advantage that the switching device can be switched off at any time by a control command and the car telephone system can be reset to the state of the art.

During the initialization phase, the second switch, which is inserted into the bypass line, is closed and the first switch is open. A data flow between the radio and the control unit is possible via the bypass line. Since the data output of the interface of the switchover device is not on the data line (the first switch is open), no signals originating from the interface itself can reach the data line. In terms of output, the interface is therefore put to death during the initialization phase. In contrast, the interface is connected to the data line via its data input. It therefore receives all data that pass through the data line during the initialization phase. As a result, it is able to record the information which means that the car telephone system is ready for operation, so that it can switch the switches together at a given time and fully integrate itself into the data line.

In the normal state after the initialization phase has ended, the radio, the interface and the control unit communicate with each other serially, all data traffic between the radio and the control unit runs through the interface. The interface is thus always informed about the current status of the overall system.

The LF lines, on the other hand, are switched over, the LF lines coming from the radio are either connected to the control unit or to the extension unit. A common supply of all three devices is not given here. The invention makes it possible to integrate an extension device according to the Stan technique in a car telephone system. If such an extension device is, for example, a cordless telephone, mobile radio subscribers have the possibility of moving a few hundred meters away from the car telephone, but can both accept and answer incoming A and set up outgoing calls via the part of the cordless telephone fully automatically and for one In this way, car telephone subscribers receive the convenience that fixed telephone systems are already available.

Another extension device can also be connected, and several extension devices can be connected to one car telephone system. When several extensions are operated, a corresponding number of switchover devices is required, the serial plug-in device is not left.

Car telephone systems of the type mentioned initially have data lines, one of which transfers data from the radio to the operator and the other data from the control unit to the radio. According to the invention, a bypass line can be seen for each data line, each of which interacts with two switches. With a simple extension device, such as an additional alarm clock, it is now not necessary that the interface used for this G is inserted in both data lines. A simple interface suffices, which is only inserted into the data line leading from the radio to the control unit. Compared to the active interface device, which in turn can also transmit, such interfaces are simpler Ge so less complex and therefore cheaper. The first second switches in the area of the data lines and the LF switch can be designed in any form, for example there may be a lack of space, the LF switch can be implemented by a relay with usually four switching tongues. Instead of mechanical switches, semiconductor switches and other switches according to the prior art are also possible. In a further development, the changeover device is designed in such a way that it has a lower priority than that of the connected extension unit. So if the handset control unit is removed at any time, any connection that may exist between the transmitter and the radio is immediately interrupted. This has the advantage, for example, that one can call the motor vehicle with a cordless telephone and pick up the handset and continue the telephone conversation with it. Most of the time, the participant at the other end will not notice this scarf.

Further advantages and features of the invention emerge from the remaining claims and the following description of an embodiment which is not to be understood as restrictive and which is explained in more detail with reference to the drawing. In this show:

1 is a schematic diagram of a car telephone system with a switching device and an extension unit in the form of a cordless telephone, the state during the initialization phase is shown,

Fig. 2 is a representation corresponding to Figure 1, the Nor state of the system is shown after completion of the initialization phase

3 shows a representation corresponding to FIG. 2, that is to say after completion of the initialization phase, but shows the state Bet of the private branch exchange.

The car telephone system shown in FIG. 1 has a radio 20, which is connected to an operating unit 22. The connection is made first via two data lines 24, 26, secondly via a total of four lines 28, 30 and via further lines which are not of interest here and of which the voltage supply device 32 is shown as an example. In the lines 24 to 30 between the radio devices 20 and the control unit, a switching device is inserted serially, to which a branch device 36 in the form of a cordless telephone is connected. The main device 38 is shown, which is in the same motor vehicle radio 20 and control unit 22 and the mobile one Part 40.

Both data lines 24, 26 are separated by inserting the switching device 34 into a first section 42 and a second section 44, respectively. In the following, the upper data line 24, which is vera verba for the data stream from the radio 20 to the control unit 22, is first discussed. The first part of this data line 24 shown on the left is connected to a data input 46 of an interface 48 of the switching device 34. However, one end of a bypass line 50 is also present at the same data input 46. The data output 52 associated with the data input 46 is not directly connected to the second section 44, but rather a first switch is interposed. The connection between this first switch and the right, second section 44 is referred to below as the knotting point 56. The other end of the bypass line 50 lies at this connection point 56. In the bypass line e second switch 58 is inserted, which is inversely ben to the first switch. If the first switch 54 is open, the two switches 58 are closed and vice versa. This scarf is controlled via a control line 60, which is shown in dashed lines. A part of this control line forms a reset line 62, via which the main device 38 is connected.

The second data line 26 is also switched and implemented, in contrast to the first data line 24, the data input of this line is, however, on the right boundary line of the interface 48, so that the arrangement appears symmetrically twisted. The switches 54, 58 of the second data line 26 are also connected to the control line 60. This means that all four switches 58 are operated simultaneously. The two NF double lines 28, 30 of the radio 20 are fed to a relay 66 with a total of four switches. The NF lines 28, 30 are located on the tongues of the changeover switch. Depending on the excitation relay, the tongues are either connected to the four AF lines 68, which lead to the control unit 22, or to the NF lines 70, which belong to the extension unit 36. It is therefore ensured that only one device, that is to say either the control unit 22 or the extension unit 36, is connected to the radio 20 in accordance with the NF. The relay 66 is controlled by a line 72 which is connected to a control output of the interface 48.

The radio 20 and the main device 38 each have an antenna line 74, 76 which is connected to a crossover 78. this is in turn a single external antenna 80. The d crossover 78 avoids the need for two antennas.

The individual operating states are now described below:

During the initialization phase shown in FIG. 1, the second switches 56 are closed, which means that the bypass lines are switched through. The first switches 54 are then open. In this state, the interface 48 can receive data via its two data inputs 46 and only, but no data _. hand over their data outputs. It behaves passively to the outside and does not actively access the data stream between radio device 20 and control unit 22. During the initialization phase, LF lines 28, 30 are connected to LF lines 68 of control unit 22, and main unit 38 is decoupled according to LF.

The operating state according to FIG. 1 also corresponds to the state of a private branch exchange which is switched off. If the interface 48 is switched off, the system shown behaves like a standard car telephone system, which only consists of a radio and an auxiliary part. Figures 2 and 3 show operating states after completion of the initiation phase. FIG. 2 shows the normal state after completion of the initialization phase. The bypass lines 50 are interrupted, after the completion of the initialization phase the second switches 58 are opened. Thus the first switches 54 are inevitably closed. The data streams in both data lines 24, 26 thus run through the interface 48, the bypass lines are practically non-existent. As in the state according to FIG. 1, the NF lines 2 30 are connected to the NF lines 68 of the control unit 22, the main device 38 is therefore decoupled according to NF.

If the operator of the control unit 22 is removed in this state, the normal operation of the car telephone system takes place, as would also take place without an additional auxiliary system. The interface 48, however, also receives all the data and ensures via a data line 82, which connects it to the main device 38, that access via the private branch exchange is blocked. It is not possible, for example, to establish a connection with the radio 20 with the mobile part 40 of the auxiliary device 36 via the main device 38. On the contrary, when the operating part of the mobile part 40 is lifted off, this indicates that no connection can be made.

In the state according to FIG. 2 and according to FIG. 3, an incoming call from the outside is forwarded to both devices, that is to say to the control unit 22 and to the extension device 36. In the motor vehicle, therefore, the control unit 22 sounds a wake-up call, and also a wake-up call sounds on the mobile part 40 of the extension unit 36. The R can be accepted by both devices and the connection can therefore be established alternatively was accepted. Figure 3 shows the state that the incoming call was accepted by the handset of the mobile part 40.

The same conditions apply to a call that is sent out: FIG. 2 shows the state as it is when a call is sent using de Control unit 22 is present. FIG. 3 shows the corresponding state b sending a call using the mobile part 40.

3, the NF lines 28, 30 are connected to the NF line 70 of the main device 38. The data lines 24, remain changed since the initialization phase has been completed.

Claims

P a t e n t a n s r u c h e

Car telephone with a radio (20) and a control unit (22) which are connected on the one hand via at least one data line (24, 26) and on the other hand via LF lines (28, 30), characterized in that the operation of an extension i Lines (24 to 30) a changeover device (34) is inserted,

- which is connected to an extension device, for example a cordless telephone, fax machine, bell or the like,

- Which has an interface (48) inserted into the data line (24, 26), which has a data input (46, 64) and one with its data output (52) via a (first) switch (54) in a connection point ( 56) is connected to the other section of the data line (24, 26), and

- The one of this interface (48) controlled LF switch ter (relay 66), which establishes an LF connection from the radio (20) either to the control unit (22) or to the extension unit (26) and that a bypass line (50) is provided,

- Into which a second switch (58) operated inversely to the first switch (54) is inserted

- The one end at the data input (46) and

- The other end is connected to the node (56).

2. Car telephone system according to claim 1, characterized in that d two data line (24, 26) are provided between the radio (20) and control unit (22) that each data line is assigned a bypass device (50), in each of which a second circuit (58) and that between the associated data output (5 and the junction point (56) of each data line (24 or 26) e first switch is arranged, all switches (54, 58) being actuated together via one control line (60).

3. car telephone system according to claim 1 or 2, characterized in that an antenna line (74) of the radio (20) and an ante nenleitung (76) of the main unit (38) of a trained as a cordless phone extension unit (36) at a frequency soft (78 ) iεt, to which a common outer edge (80) is applied.