EP2733676B1 - Method and system for preventing tampering in e-ticketing systems - Google Patents

Description

The present invention relates to a tamper-resistant method and a system for registering a defined presence according to the patent claim 1 or the patent claim 10.

For example, the general functionality and requirements for an e-ticketing system in a public transport vehicle can be found in the sources given in [2] and [3]. Electronic tickets or electronic tickets are also known as e-tickets. In the following, the aforementioned two terms are briefly subsumed under e-ticket. Likewise, vehicles of the OeV - as well as course ships - are subsumed under the term (public) means of transport.

Essentially two different ticketing systems are distinguished:

CiCo check-in / check-out

• Proximity, ISO/IEC 14443,
  Reichweite bis 10cm;
• Vincinity, ISO/IEC 15693, 13.56MHz;
  Reichweite 1 - 1.5m.

A passenger deliberately holds his ticket just before entering and leaving the means of transport or the platform area in front of one of the billing system belonging readers, correctly "transceiver units". The query of the ticket - hereinafter referred to as e-ticket - is done by a near-distance radio link, such as

• Proximity, ISO / IEC 14443,
  Range up to 10cm;
• Vincinity, ISO / IEC 15693, 13.56MHz;
  Range 1 - 1.5m.

BiBo Be-in / Be Out

For more comfortable systems, it is only necessary that the passenger carries his electronic ticket: the ticket is automatically transferred by radio to the cars within the sections of the route installed reading units detected and fed the data thus obtained an automatic accounting system. An interaction of the user is no longer necessary. It also does not need a check-out process. Thus, the flow of passengers can be accelerated considerably, especially when passengers are getting in / out at the same time.

• Aus Gründen der Autonomie befinden sich die Billette in einem Schlafzustand. Beim Eintritt in ein Verkehrsmittel werden die e-Tickets durch ein Nahfeld, z.B. mit einer Arbeitsfrequenz von 6.78MHz geweckt und unidirektional mit einer ID sowie einer Timing Information «gestempelt». Die ID bezieht sich auf den im Eingangsbereich befindlichen Wecksender und die Timing Information auf Beginn und Intervall einer bidirektionalen Kommunikation zwischen e-Ticket und einer im Wagen befindlichen Sende- und Empfangseinheit. Durch das Protokoll können bei diesem System Fehlerfassungen und Manipulationen verhindert werden, so z.B.
  • Parallelfahrt auf einem Velo oder durch Parallelfahrt zweier Züge
  • Betrugsversuche durch temporäres Versorgen des e-Tickets in eine metallene Zigarettenschachtel.

From the Scriptures EP 1 201 693 B1 [1] discloses a method and system for acquiring electronic tickets (e-ticket). The system disclosed in document [1] is based on the following functionality:

• For reasons of autonomy, the tickets are in a sleep state. When entering a means of transport, the e-tickets are awakened by a near field, eg with an operating frequency of 6.78 MHz and "stamped" unidirectionally with an ID and timing information. The ID refers to the wake-up transmitter located in the entrance area and the timing information to the beginning and the interval of bidirectional communication between the e-ticket and an in-car transmitter and receiver unit. The protocol can be used with this system to prevent errors and manipulation, such as
  • Parallel travel on a bicycle or by parallel travel of two trains
  • Fraud attempts by temporarily supplying the e-ticket in a metal cigarette box.

An e-ticket as described above can only be detected if the necessary radio links between the e-ticket and installed in the transport transmitter / receiver units actually come about, and only then can the one trip made properly settled on a background system become.

Unlawful users could try to manipulate the capture of an e-ticket so that a regular billing does not occur or can not be done. On the one hand Therefore, for an e-ticket system at least rudimentary carrying and user instructions for the passengers must be issued, which prevent the e-ticket is worn more or less completely shielded. On the other hand, there must be appropriate system engineering measures to prevent manipulation.

1. i) Störsender, die die Kommunikation zwischen elektronischer Fahrkarte und Systemkomponenten im Zug verhindern;
2. ii) Schädigung/Zerstörung von elektronischen Fahrkarten durch hohe HF-Pulsleistungen;
3. iii) Schädigung/Zerstörung von Systemkomponenten durch hohe HF-Pulsleistungen.

Some manipulation options are listed below:

1. i) jammers that prevent communication between electronic ticket and system components on the train;
2. ii) damage / destruction of electronic tickets due to high RF pulse power;
3. iii) damage / destruction of system components by high RF pulse power.

Bringing jammers in the car, for example, the radio communication and possibly the Aufweckvorgänge - with which the e-tickets are transferred to an interactive state - temporarily disturb or prevent. If in such a case a billet resp. Ticket inspection, all passengers in the area concerned would not be able to produce a valid e-ticket, which also means that unlawful users - referred to below as saboteurs - can no longer be prosecuted.

Another method of manipulation is high-frequency radio transmitters brought along. When a saboteur hides such a jammer, he or she could permanently damage or destroy the e-tickets of other passengers in the vicinity (too high in the high-frequency part power level). Possible biological effects on passengers will not be further explained at this point. Such jammers have the consequence that in the case of a ticket control several passengers can show and thus a black driver can not be prosecuted.

Similarly, when a high-frequency, high frequency transmitter is used to permanently damage or destroy transmitter / receiver units installed in the car. Although these transceiver units are usually installed in comparatively inaccessible installation locations in the car. Since the damage or destruction takes place via radio field, this can also happen over a certain distance. The consequence would again be, as in the cases mentioned above, the condition that several passengers at the same time can not present a duly registered e-ticket.

Correspondingly high RF pulse powers can damage not only the high-frequency part of the electronic tickets and system components installed in the car, but also other circuit parts. This would result in similar effects as previously described.

The DE102006015237B3 shows a method for registering passenger travel in a public transport. Electronic tickets are automatically recorded and canceled here.

1. i) solche Störungen detektieren und signalisieren können
   und
2. ii) die immun sind gegen mittels Störsender erfolgende Manipulationen.

The present invention is therefore based on the object of specifying a method for registering a defined presence of e-tickets and an e-ticketing system, which

1. i) can detect and signal such interference
   and
2. ii) that are immune to jamming manipulations.

This object is achieved by the measures specified in the independent claims 1 and 10. Advantageous embodiments of the invention are specified in further claims.

1. i) Referenzmarken können besonders kostengünstig realisiert werden, wenn sie konstruktiv und funktional gleich wie die e-Tickets ausgebildet sind. Da die Grösse der e-Tickets der Grösse einer üblichen Kreditkarte entspricht, ist auch deren Einbau sehr einfach.
2. ii) Durch in der Sende-/Empfangseinheit implementierte Algorithmen kann die Unterscheidung der Identnummer der Referenzmarken von der Identnummer eines e-Tickets «lernend» vorgenommen werden, da die fest installierten Referenzmarken auch ausserhalb des eigentlichen Betriebszeiten (für das Publikum) registriert werden.
3. iii) Ein in einer Sende-/Empfangseinheit erkannter Ausfall kann bedürfnisgerecht weiter signalisiert werden, innerhalb des betreffenden Verkehrsmittels wie auch ausserhalb des betreffenden Verkehrsmittel, z.B. auch an eine abgesetztes übergeordnetes System.

This may result in the following additional benefits:

1. i) reference marks can be realized particularly cost-effective, if they are constructively and functionally the same as the e-tickets are formed. Since the size of the e-tickets is the size of a standard credit card, their installation is very easy.
2. ii) By implemented in the transmitting / receiving unit algorithms, the distinction of the ID number of the reference marks of the ID number of an e-ticket "learning" can be made because the fixed reference marks are registered outside of the actual operating hours (for the public).
3. iii) A failure detected in a transceiver unit can be further signaled as needed, within the relevant means of transport as well as outside the relevant means of transport, eg also to a remote superior system.

• Figur 1 Querschnitt durch einen Eisenbahnwagen mit den Komponenten zur Detektion und Signalisierung von mitgeführten Störsendern.

The invention will be explained in more detail with reference to the drawing, for example. Showing:

• FIG. 1 Cross section through a railway carriage with the components for the detection and signaling of entrained jammers.

FIG. 1 shows a cross section through a railway carriage 30 as an example of a means of transport 30. On the ceiling of the railway carriage 30, two transceiver units 20 ₁ and 20 _{2 are} installed. These transmitting / receiving units 20 ₁ and 20 ₂ are each provided with an antenna 19. For the transmitting / receiving unit 20 ₁ , the associated detection area 21 is shown. Within this detection range 21, e-tickets 10 can record a communication with the transmitting / receiving unit 20 ₁ , which as a result is used to register the e-tickets 10 for the accounting of a related mileage. In the FIG. 1 the e-tickets are shown so that they can not establish a bidirectional communication via the transceiver unit 20 ₁ , but with the transceiver unit 20 ₂ . Due to the illustrated situation, the upper e-ticket 10 can be assigned to a passenger, while the lower e-ticket can be assigned to a piece of luggage or a dog.

In order to ensure the function of an e-ticket system in a means of transport 30, additional reference marks 110 (also called radio beacons 110) are permanently but concealedly installed at various installation locations in the means of transport 30 for each detection area. Constructively, these reference marks 110 may be the same or similar to the e-tickets 10 for the passengers, dogs and luggage.

• Funkbake 110₁ fest hinter der Wandverkleidung zur Aussenwand 33 installiert;
• Funkbake 110₂ fest in oder an einer Trennwand 34 installiert;
• Funkbake 110₃ fest in einem Deckel eines Abfallbehälters 35 eingebaut.

According to the FIG. 1 these wireless beacons 110 are installed as follows:

• Radio beacon 110 ₁ fixed behind the wall cladding to the outer wall 33 installed;
• Radio beacon 110 ₂ fixedly installed in or on a partition wall 34;
• Radio beacon 110 ₃ permanently installed in a lid of a waste container 35.

• Die Sende-/Empfangseinheiten 20 führen eine Historie/History der erfassten Identnummern von e-Tickets 10 und von Referenzmarken 110. Während bei den e-Tickets 10 im Verlaufe der Erfassung verschiedenen Identnummern neu hinzukommen und nach Abschluss einer Fahrt nicht mehr erfasst werden, trifft dies für die Referenzmarken so nicht zu. Die Referenzmarken 110 werden permanent - permanent im vorgesehen Zyklus bzw. Periodizität - von der Sende-/Empfangseinheit 20 erfasst, insbesondere auch an einer Endhaltestelle oder in einem Depot. Diese Betriebszustände «Endhaltestelle» - ggf. mit einem Fahrtrichtungswechsel - oder «Verweilen im Depot» oder «Dienstfahrt» sind bei den meisten Erfassungssystemen mit einer Sende-/Empfangseinheit 20 codiert vorhanden, da einem Verkehrsmittel 30 nicht nur die aktuelle Uhrzeit, sondern auch der Kurs mit einer Kursnummer zuzuweisen ist. So muss sich z.B. ein Buschauffeur oder ein Lokomotivführer beim Dienstbeginn einloggen und zwar mit
  • persönlicher ID, z.B. Kennung und Passwort;
  • Dienstnummer;
  • Kurs-ID.
• Diese Angaben werden von einem Fahrzeug- bzw. Bordrechner administriert und sind auch der Sende-/Empfangseinheit 20 mindestens bezüglich Kurs-ID und Fahrzeug-ID zugänglich.

These radio beacons 110 are correspondingly "trained" to the installed in the railway carriage 30 transceiver units 20 with ID number and associated key for bidirectional communication. The "learning" can be configured as follows:

• The transceiver units 20 keep a history of the detected ID numbers of e-tickets 10 and reference marks 110. While in the e-tickets 10, different ID numbers are newly added in the course of the acquisition and are not detected after completion of a trip, it is true this is not the case for the reference brands. The reference marks 110 are detected permanently - permanently in the intended cycle or periodicity - by the transmitting / receiving unit 20, in particular also at an end stop or in a depot. These operating conditions "final stop" - possibly with a change of direction - or "staying in the depot" or "business trip" are encoded in most detection systems with a transmitting / receiving unit 20, since a transport 30 not only the current time, but also the Course with a course number is assigned. For example, a bus driver or a locomotive driver must log in at the beginning of the service and that with
  • personal ID, eg ID and password;
  • Service number;
  • Course ID.
• This information is administered by a vehicle or on-board computer and are also accessible to the transceiver unit 20 at least in terms of course ID and vehicle ID.

The teach-in process described above will still work even if someone consciously leaves one or more e-tickets 10 in a train compartment at a hidden location, eg at the rear of the upper luggage rack (for light carry-on luggage) on a hidden or barely visible one Job. Later - after automatic learning has taken place - these e-tickets 10 deposited in this way could be removed again and thus specifically trigger a (fake) fault message. The same thing happens when accidentally e-tickets are lost in a compartment. In order to prevent such manipulations as well, the number range of the ident numbers for the reference marks is created disjoint to the number range for the ident numbers of the e-tickets. This attachment of the number ranges can also be made such that the number range of the reference marks and the number range of the e-tickets 10 correspond to a certain algorithm, e.g. even or odd. Likewise, a separate contiguous number range for e-tickets 10 and reference marks 110 can also be provided.

1. i) Der Ausfall einer einzigen Referenzmarke 110 dauert länger als ein vorgegebenes Zeitintervall, typische Beispielwerte: 5min, 10min, 15min.
2. ii) Mehrere Referenzmarken 110 werden nicht mehr erfasst.
3. iii) Kumulation der Kriterien i) und ii) wobei als typische Beispielwerte kürze Zeiten vorzusehen sind: 2min, 4min, 6min.

The transceiver units 20 cyclically attempt to detect these reference beacons 110. If a bidirectional communication can no longer be established with one of these reference marks 110, this is detected by the respective transmitting / receiving unit 20. The relevant transceiver unit 20 can pass on such a failure as a fault to a higher-level system such as vehicle computer or remote system. The remote system is coupled to the transport 30 via another radio link. For the detection of an actual failure, various criteria can be specified:

1. i) The failure of a single reference mark 110 lasts longer than a given time interval, typical example values: 5min, 10min, 15min.
2. ii) Several reference marks 110 are no longer detected.
3. iii) accumulation of criteria i) and ii) being typical Example values to be provided shortly: 2min, 4min, 6min.

Defects in the transmitting / receiving units 20 themselves can also be detected by the higher-level system insofar as it can be established by means of a protocol that a status message is output to the higher-level system in a specific time frame. As a result, sudden defects in circuit parts of a transmitting / receiving unit 20 in the means of transport 30 can be detected, which can not be found despite self-test mechanisms.

Now, if many people are in the passenger compartment of a car 30, it may happen that one of the reference marks 110 is shadowed by the persons concerned. But if z. B. no longer detected by a introduced into the passenger compartment by a saboteur jammer or a technical defect in the transmitting / receiving unit 20 more than a reference mark 110, the transmitting / receiving unit 20 would issue a corresponding fault message to the parent system, therein could also be a notification to the locomotive driver or the ship's captain, if permitted by the regulations. The same reaction would result if a larger number of reference marks 110 would no longer be interrogated, which are destroyed, for example, by very high RF pulse powers of a jammer brought along. Instead of notifying the locomotive driver or the captain of the ship, it is also possible to notify transport police officers (uniformed or undercover) who are patrolling the transport 30. The presence of such emergency services can be particularly recognized by the transceiver units 20 located in the means of transport 30. This recognition takes place via a special identification number of the e-tickets 10 of the officials of the transport police. Emergency personnel can be notified on special TETRAPOL radios (within the TETRAPOL system for BOS organizations).

1. i) Die Kommunikation zwischen einer Sende-/Empfangseinheit 20 und den zugeordneten Referenzmarken 110 wird auch für einen automatischen Selbsttest, insbesondere für einen automatischen Selbsttest der Sende-/Empfangseinheit 20 in einem Verkehrsmittel 30 herangezogen.
2. ii) Die Energieversorgung der fest eingebauten Referenzmarken 110 erfolgt über entsprechend in einem Verkehrsmittel 30 installierte Leitungen mit Energie.
3. iii) Die Energieversorgung der fest eingebauten Referenzmarken 110 erfolgt dadurch, dass die Referenzmarken 110 die benötigte elektrische Energie aus in ihrer Umgebung zur Verfügung stehenden Energieformen beziehen, wie
   • Licht (Photovoltaik),
   • Beschleunigungs- und Abbremsvorgänge, Vibration,
   • Temperaturänderungen.
4. iv) Die Referenzmarken 110 sind wie normale e-Tickets 10 oder ähnlich dazu ausgebildet und werden in passenden Bauteilen eines Verkehrsmittels 30 eingefügt, wobei diese Bauteile z.B. verdeckte Aussparungen für die Montage dieser e-Tickets enthalten können. Dadurch wird ein Wechsel der Referenzmarken 110, z. B. im Falle verbrauchter Batterien, ganz erheblich erleichtert.
5. v) Die Referenzmarken 110 sind an beweglichen aber dem Verkehrsmittel zugeordneten Elementen angebracht. Dadurch kann über dieses sog. e-Ticketing-System zusätzlich erkannt werden, ob eines dieser Elemente entwendet oder beschädigt wird. Solche vorstehend genannte Elemente sind beispielsweise:
   • Feuerlöscher;
   • Einschlaghämmer für die Evakuation im Fall einer Entgleisung eines Zuges oder eines Absturzes eines Busses in ein tiefes Tobel;
   • Verriegelungen für die mechanische Handbremse;
   • Kleiderbügel in den Abteilung der gehobenen 1. Klasse;
   • Rettungsringe;
   • Rettungsboote;
   • Keile zur Sicherung von Bussen gegen unbeabsichtigtes Wegrollen.

The following advantageous embodiments of the aforementioned arrangement of reference marks 110 are to be additionally provided:

1. i) The communication between a transmitting / receiving unit 20 and the associated reference marks 110 is also used for an automatic self-test, in particular for an automatic self-test of the transmitting / receiving unit 20 in a means of transport 30.
2. ii) The power supply of the fixed reference marks 110 is carried out via appropriately installed in a means of transport 30 lines with energy.
3. iii) The power supply of the fixed reference marks 110 takes place in that the reference marks 110 draw the required electrical energy from available forms of energy in their environment, such as
   • Light (photovoltaic),
   • Acceleration and deceleration processes, vibration,
   • Temperature changes.
4. iv) The reference marks 110 are like normal e-tickets 10 or similar formed and are inserted in appropriate components of a means of transport 30, which components may include hidden recesses for the assembly of these e-tickets. As a result, a change of the reference marks 110, z. B. in the case of spent batteries, greatly facilitated.
5. v) The reference marks 110 are attached to movable but assigned to the transport elements. This makes it possible to additionally detect via this so-called e-ticketing system whether one of these elements is being stolen or damaged. Such elements mentioned above are, for example:
   • fire extinguishers;
   • Impact hammers for evacuation in case of derailment of a train or a crash of a bus into a deep ravine;
   • Locks for the mechanical handbrake;
   • Hangers in the department of the upper 1st class;
   • Lifebelts;
   • Lifeboats;
   • Wedges for securing buses against unintentional rolling away.

The aforementioned advantageous embodiments for the reference marks 110 are freely combinable with the algorithms implemented in the transceiver unit 20, such as the "teaching" of reference marks 110, and also freely combinable with the various signaling options disclosed above.

List of reference numbers, glossary

10

e-ticket, position of an e-ticket

110

Radio beacon, reference mark

110 ₁

Radio beacon, reference mark installed behind wall cladding

110 ₂

Radio beacon, reference mark installed in partition

110 ₃

Radio beacon, reference mark installed in the lid of a waste container

19

Antenna of a transmitting / receiving unit

20, 20 ₁ , 20 ₂

Transmit / receive unit

21

Detection range of a transmitting / receiving unit 20

30

transport; Railway carriage, ship, bus

33

outer wall

34

Partition entrance / passenger compartment with seats; Partition between two areas of the means of transport

35

Waste container, attached to wall 33

BOS

Authorities and organizations with security responsibilities

HF

high frequency

OeV, public transport

Public transport

List of cited documents

1. [1] EP 1 201 693 B1
   «Method and system for registering tickets»
2. [2] «e-Ticketing»
   Siemens Switzerland Ltd, Industry Sector, Mobility Division, Rail Automation www.litra.ch/download.php?file=dcs/users/2/3 20110316 MF dt.pdf
   and http://www.litra.ch/dcs/users/2/3 20110316 MF dt.pdf
   Internal file number: 2012Q25342.
3. [3] «Content and structure of specifications / customer interface and certification in the VDV core application» Presentation by Dipl.-Ing. Elke Fischer
   VDV-KERNAPPLIKATIONS GmbH & Co. KG http://www.eticket-deutschland.de/
   Internal file number: 2012Q25342.

Claims (15)

1. Method for registering a defined presence of e-tickets (10) in a means of transport (30), wherein the e-tickets (10) contain transmit/receive means for a radio communication with a transmit/receive unit (20) arranged in the means of transport (30), during which radiocommunication data for registering the defined presence of e-tickets (10) is transferred to the transmit/receive unit (20),
   characterised in that
   reference markers (110, 110₁, 110₂, 110₃) are permanently installed in the means of transport (30), the presence of which in the means of transport (30) is registered in the same way as the e-tickets (10) and a failure of a subsequent registration of a reference marker (110, 110₁, 110₂, 110₃) is evaluated as a malfunction by the transmit/receive unit (20) and is indicated, wherein

   i) the reference markers (110, 110₁, 110₂, 110₃) are embodied to be structurally the same as the e-tickets (10), and

   ii) an identity number of the reference marker (110) is transferred to the transmit/receive unit (20) during the radio communication and the transmit/receive unit (20) is taught by the permanent recording to recognise the transferred identity number as an identity number of a reference marker (110).
2. Method according to claim 1,
   characterised in that
   the identity numbers of a reference marker (110) are taught in that these identity numbers are also recorded in special operating states outside of regular operation and are as result recognised as identity numbers of a reference marker (110).
3. Method according to claim 2,
   characterised in that a change in direction of travel at a terminal stop or a re-allocation of a route number or the waiting time in a depot is used as a special operating state in order to recognise a recording of an identity number as an identity number of a reference marker (110).
4. Method according to claim 2,
   characterised in that
   the identity numbers of a reference marker (110) are taught such that a history of the registered identity numbers of reference markers (110) and of e-tickets (10) is conducted in the transmit/receive unit (20) and an assignment of identity numbers to reference markers (110) is performed on the basis of this history.
5. Method according to one of claims 2 to 4,
   characterised in that
   a separate number range is provided for the e-tickets (10) and the reference markers (110) in each case.
6. Method according to one of claims 1 to 5,
   characterised in that
   the failure of a registration of a reference marker (110) is only then indicated as a malfunction if this failure exceeds a predetermined time interval.
7. Method according to one of claims 1 to 5,
   characterised in that
   the failure of a registration of reference markers (110) only then indicates a malfunction if at least two reference markers (110) are no longer registered.
8. Method according to claim 7,
   characterised in that
   a malfunction is only then indicated if the failure exceeds a predetermined time interval.
9. Method according to one of claims 1 to 8,
   characterised in that
   the malfunction is indicated to a system upstream of the transmit/receive unit (20).
10. System for registering a defined presence of e-tickets (10) in a means of transport (30), wherein the e-tickets (10) contain transmit/receive means for a radio communication with a transmit/receive unit (20) arranged in the means of transport (30), during which radio communication (41) data for registering the defined presence of the e-ticket (10) is transferred to the transmit/receive unit (20),
    characterised in that
    reference markers (110, 110₁, 110₂, 110₃) are permanently installed in the means of transport (30), the presence of which in the means of transport (30) is registered in the same way as the e-tickets (10) and a failure of a subsequent registration of a reference marker (110, 110₁, 110₂, 110₃) is evaluated by the transmit/receive unit (20) as a malfunction and is indicated, wherein

    i) the reference markers (110, 110₁, 110₂, 110₃) are embodied to be structurally the same as the e-tickets (10), and

    ii) that means are available in order to transfer an identity number of the reference marker (110) to the transmit/receive unit (20) during the radio communication and that means are also available so that the transmit/receive unit (20) is taught by the permanent recording to recognise the transferred identity number as an identity number of a reference marker (110).
11. System according to claim 10,
    characterised in that
    the reference markers (110, 110₁, 110₂, 110₃) are installed concealed in the means of transport (30).
12. System according to claim 10 or 11,
    characterised in that
    the reference markers (110, 110₁, 110₂, 110₃) are installed concealed in fixedly integrated elements (33, 34, 35) assigned to the means of transport (30) and as a result a wilful removal of these elements and thus a failure of the registration of the reference markers (110) can be recognised as a malfunction.
13. System according to claim 10 or 11,
    characterised in that
    the reference markers (110, 110₁, 110₂, 110₃) are installed concealed in moveable elements assigned to the means of transport (30) and as a result a wilful removal of these elements and thus a failure of the registration of the reference markers (110) can be recognised as an malfunction.
14. System according to one of claims 10 to 13,
    characterised in that
    the reference markers (110, 110₁, 110₂, 110₃) are supplied with energy, which emanates from energy which is available from its environment by means of a corresponding energy transducer.
15. System according to claim 14,
    characterised in that
    provision is made for energy transducers in the form of

    - solar cells for converting light into electrical energy or

    - a component, which transforms developing accelerations into electrical energy;

    - a component which transforms temperature changes into electrical energy.

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