Emergency call unit for an ecall system

Abstract

The invention relates to an emergency call unit (100) for an eCall system, comprising: an input interface (170) for audio signals which is designed to be coupled to a microphone (102); an output interface (150) for outputting audio signals which is designed to be coupled to a sound-generating transducer (101); a modulation device (120) which is designed to modulate an original audio signal (Xr) by means of a first data code (Ds) and to provide a resulting modulated audio signal (Xa) to the output interface (150) in order to generate an emitted sound signal (Xn) via the sound-generating transducer (101); and a demodulation device (130) which, in order to determine a second data code (Dt), is designed to demodulate an audio signal (Yn) which is induced by the emitted sound signal (Xn), is generated by means of the microphone, and is provided to the input interface (170); wherein the emergency call unit (100) and / or a signal-connected emergency service device (200) is designed to verify an acoustic path (A) between the sound transducer (101) and the microphone (102) by comparing the first data code (Ds) with the second data code (Dt).

Description

[0001] Description

[0002] EMERGENCY CALL UNIT FOR AN eCALL SYSTEM

[0003] Field of invention

[0004] The present invention relates to an emergency call unit for an eCall system, an emergency call service device for an eCall system and an emergency call system.

[0005] background

[0006] A unit for an emergency call system, now largely mandated by law in new vehicles, must enable secure audio communication with vehicle occupants and emergency services reachable via a mobile network, such as the police or ambulance service. The security-verified audio output path can be simple or technically sophisticated, featuring its own security-verified audio processing elements.

[0007] Summary

[0008] The invention describes an emergency call unit for an eCall system, an emergency call service device for an eCall system, and an emergency call system according to the features of the independent claims. Advantageous embodiments are the subject of the dependent claims and the following description.

[0009] One aspect of the invention relates to an emergency call unit for an eCall system, wherein the emergency call unit has an input interface for providing audio signals, an output interface for outputting audio signals, a modulation device, and a demodulation device. The input interface for audio signals is configured to be coupled to a microphone. The output interface for outputting audio signals is configured to be coupled to a sound-generating transducer.

[0010] - The modulation device is set up to modulate an original audio signal using an initial data code and to provide a resulting modulated audio signal to the output interface in order to generate an emitted sound signal by means of the sound-generating transducer.

[0011] - The demodulation device is set up to demodulate an audio signal induced by the emitted sound signal and generated by the microphone, which is provided at the input interface, in order to determine a second data code.

[0012] - The emergency call unit and / or a signal-linked emergency service facility is set up to verify an acoustic path between the transducer and the microphone by comparing the first data code with the second data code.

[0013] The first data code may be randomly generated and / or contain characterizing information, for example from a module of the emergency call unit that generates the first data code and / or the signal-linked emergency service facility.

[0014] In particular, the demodulation unit can be configured to determine the second data code based on the generated audio signal and the original audio signal. Advantageously, the emergency call unit can be configured to transform the generated audio signal using an impulse response of the acoustic path, based on a convolution operation with the impulse response, in order to at least partially compensate for time-of-flight effects on the acoustic path that affect a waveform of the generated audio signal for demodulation purposes.

[0015] The output interface can be configured with an amplifier to provide the modulated audio signal so that the sound-generating transducer, such as a loudspeaker, can be directly connected. The emergency call unit and / or the signal-linked emergency service equipment can be configured to generate the initial data code and / or the original audio signal, particularly for verifying the acoustic path. Alternatively or additionally, the initial data code and / or the original audio signal can be transmitted from the emergency service equipment to the emergency call unit, particularly wirelessly, as described below.

[0016] In this process, a radio signal exchanged between the emergency call unit and the emergency service facility can transmit the original audio signal and the first data code separately, either technically or temporally. By transmitting the first data code separately from the original audio signal, the radio signal ensures that the first data code is transmitted, unlike with a modulated audio signal. This is because audio data compression, typically used for mobile communication, could severely distort such a modulated signal. This is especially true if the modulation includes signal components that may be irrelevant to human hearing.

[0017] Advantageously, separate transmission prevents an echo compensation and noise reduction unit, such as an EC / NR unit (echo compensation and noise reduction unit) of the emergency call unit and / or the emergency service facility, from filtering out the directly transferred original audio signal of the emergency service facility, thus making direct verification of the modulated audio signal and / or the generated audio signal by signals transmitted in the mobile network from the emergency call unit, for example, a vehicle, impossible.

[0018] The original audio signal can be modulated, for example, with temporal sequences of different frequencies. The first data code defines a sequence and duration of these different frequencies, which are then modulated by the modulation device, for example, using amplitude modulation. The different modulation frequencies can be low frequencies, particularly between 10 Hz and 100 Hz, and / or high frequencies, particularly between 10 kHz and 100 kHz.

[0019] The emergency call unit, for example using the demodulation device, and / or the emergency service unit may be set up to generate a comparison result indicating that the acoustic path is functionally established if the first data code matches the second data code.

[0020] In particular, the emergency call unit can be functionally and technically designed in such a way that the emergency call unit can be certified in terms of safety.

[0021] Advantageously, the emergency call unit and the corresponding modulation of the original audio signal allow verification of whether specific audio signals, intended for communication in a particular location, such as the interior of a vehicle, have actually been audibly emitted at that location. Thus, the emergency call unit provides technically reliable feedback, for example, to the emergency services facility that is communicatively linked to the unit, as to whether the acoustic path, or, as described below, the entire transmission path or electroacoustic communication loop, is functioning correctly. This eliminates the need for an operator of the emergency services facility to assess functionality, for example, by analyzing characteristic background noises, if a vehicle occupant fails to respond.Thus, the emergency call unit can ensure a functioning communication link between two locations even if a called party does not respond.

[0022] This can be particularly relevant in the event of accidents, where the technical availability of communication equipment may be impaired or defective.

[0023] In other words, the use of the emergency call unit allows an emergency service to technically monitor the entire transmission path, including the acoustic path, for example, within a vehicle. This can assure the emergency service, provided the transmission path is functioning, that acoustic instructions and information have actually been transmitted, even if, for example in critical accident situations, no communication with an occupant is possible, or if, for example in the case of use by the police, the occupant intentionally does not respond to the emergency service's instructions.

[0024] According to one aspect, it is proposed that the modulation device be configured to modulate the original audio signal, in particular by means of a selection of the first data code; and / or a selection of a modulation method; and / or by means of a strength of the modulation; and / or by means of a size of the amplitude of the modulation, in particular compared to the amplitude of the signal; and / or by means of a frequency of the modulation, in such a way that the modulation of the original audio signal is not disturbing to a human listener.

[0025] Alternatively or additionally, the modulation device can be set up so as not to reduce the intelligibility of the modulated audio signal compared to the original audio signal.

[0026] Particularly advantageously, the modulation device can be configured such that a difference between the modulated audio signal and the original audio signal is perceptible but not disturbing, or is below an acoustic perception threshold of human hearing, wherein it is particularly technically possible to recover the second data code from the generated audio signal and / or the modulated audio signal, preferably by means of demodulation.

[0027] The modulation device can be configured to model the original signal using frequency modulation, amplitude modulation, signal-power modulation, and / or other modulation techniques. One proposed aspect is that the modulation device be configured to modulate the original audio signal in such a way that the second data code can be determined using the power spectrum of the modulated audio signal. Using such modulation techniques, which modify the power spectrum of a demodulated audio signal, it is possible to reliably demodulate and / or detect the second data code even at low modulation levels.

[0028] According to one aspect, it is proposed that the emergency call unit be set up to decouple the modulation device from the demodulation device with respect to the first data code and / or the second data code, in order to be able to certify the emergency call unit as secure with respect to its functionality.

[0029] Advantageously, this allows the emergency call unit to be functionally certified from a safety perspective. This is because decoupling the modulation unit from the demodulation unit, as a result of the emergency call unit's architecture, means that the second data code to be detected can only be detected via the acoustic path. For example, the emergency call unit can be built with spatially and / or functionally separate memory or memory areas, with one of the separate memory units being coupled to the modulation unit and another to the demodulation unit.Alternatively or additionally, separate data spaces can be set up for the modulation unit and the demodulation unit, in particular with secure operating system processes and / or secure hypervisor partitions and / or with their own computing nodes including their own data storage, so that processes assigned to the modulation unit or the demodulation unit are executed in a strictly data-technical separation from an implementing computer program.

[0030] Advantageously, the described emergency call unit can be certified for security purposes by requiring only a few components to undergo security qualification and / or by providing proof of non-interference, particularly with regard to the modulation and demodulation units. This can be achieved, for example, through existing secure operating systems / hypervisors or secure hardware infrastructure, and especially through largely separated processing cores on a "system on a chip".

[0031] According to another aspect, it is proposed that the emergency call unit be configured to provide the original audio signal and / or the first data code in order to verify the acoustic path between the sound-generating transducer and the microphone, particularly when triggered periodically and / or externally, by comparing the first data code with the second data code. For this purpose, the emergency call unit may be configured to generate and / or store the original audio signal and / or the first data code.

[0032] According to one aspect, the emergency call unit includes a wireless first communication module for communicating with an emergency call center. This first communication module can be configured to provide the initial audio signal and / or the first data code from the emergency call center, particularly through wireless communication. Furthermore, the emergency call unit can be configured to transmit the second data code from the emergency call center via the wireless first communication module. This allows the emergency call center to verify an electroacoustic communication loop to and from the emergency call center, including the acoustic path between the transducer and the microphone. This is particularly important because the emergency call center generates and / or provides a code, the first data code, and wirelessly transmits this first data code to the emergency call unit.The second data code, derived from the first data code and provided by the emergency call unit and wirelessly transmitted to the emergency service facility, can then be compared by the emergency service facility with the first data code to verify the electroacoustic communication loop. If the first and second data codes match, a functionally established communication loop can be inferred.

[0033] The original audio signal and / or the first data code and / or the second data code can be transferred via a data channel of the wireless connection between the emergency call unit and the emergency service facility. For example, the data channel could be a cellular network data channel.

[0034] Advantageously, proof of a functionally structured communication loop can be used to verify that communication has taken place.

[0035] It is advantageous that the emergency call unit can be set up,

[0036] - to provide and / or generate a signature code and / or a digital signature and / or a digital certificate; and

[0037] - to send the second data code, certified with the signature code and / or digital signature and / or digital certificate, to the emergency call service facility in order to authenticate the second data code of the emergency call unit based on the signature code and / or digital signature and / or digital certificate.

[0038] The signature code, digital signature, or digital certificate can be based on asymmetric encryption. The emergency call unit can have a storage area for the respective private key and / or public key and / or digital certificate. The emergency service facility can be configured to retrieve the corresponding public key from a list, with the assignment being made, for example, by means of a serial number that is transmitted from the emergency call unit to the emergency service facility along with an emergency code C. Alternatively or additionally, the emergency call unit can be configured to transmit a public key to the emergency service facility in the event of an emergency. Alternatively or additionally, the first data code can be transmitted to the emergency call unit in encrypted form, and the original audio signal can be modulated with the encrypted first data code.

[0039] According to one aspect, it is proposed that the emergency call unit be configured, in particular, to transmit any audio signals provided by the input interface to the emergency service facility via the wireless first communication module. Specifically, the emergency call unit may include a signal conditioning module configured to remove the modulated audio signal Xa from the audio signals Ym provided by the input interface before the audio signals are transmitted to the emergency service facility.

[0040] For this purpose, the signal processing module can be coupled with the first interface and an output of the modulation device to provide the demodulated audio signal and / or the first communication module to provide the original audio signal.

[0041] Advantageously, this ensures that audio signals acting on the acoustic path together with the modulated audio signal are transmitted to the emergency service facility as clearly as possible.

[0042] Advantageously, the signal processing module can be configured to remove echoes and / or noise from the provided audio signals. This can improve communication with the emergency services.

[0043] According to one aspect, it is proposed that the emergency call unit include an emergency detection unit which is configured to detect an emergency and / or accident, in particular by means of signal coupling with an accelerometer; and / or a camera; and / or a bodily function sensor; and / or a manually operated trigger. Specifically, the emergency call unit may be configured, upon detection of an emergency and / or accident, to transmit audio signals provided by the input interface and / or the digital signature and / or digital certificate and / or emergency data provided by the emergency detection unit to the emergency service facility via the wireless first communication module, for example, via a data channel of the wireless coupling between the emergency call unit and the emergency service facility.

[0044] According to one aspect, it is proposed that the input interface be configured to be coupled to a plurality of microphones, and in particular, that the respective signals of the plurality of microphones be superimposed as a single overall signal. This would allow a single microphone signal to be generated using the plurality of microphones in an emergency, in order to transmit as many individual microphone signals as possible to an emergency service facility.

[0045] According to another aspect, it is proposed that the input interface has a beamforming module which is set up to determine the position of sources of acoustic signals using the majority of the microphones in order to improve the transmission of audio signals from the input interface to the emergency service facility and / or to provide the respective signals of the majority of the microphones superimposed as a total signal.

[0046] The majority of microphones may also include microphones that are required for the emergency call system and may be installed in positions in a vehicle that are particularly protected.

[0047] According to one aspect, it is proposed that the input interface has a filter module in order to improve the transmission of audio signals from the input interface to the emergency service facility by means of frequency filtering of audio signals from at least one microphone, in particular the multitude of microphones.

[0048] According to one aspect, it is proposed that the emergency service facility be set up to cooperate with a telematics control unit (TCU), in particular that the emergency service facility be set up to cooperate with the telematics control unit.

[0049] An emergency response unit for an eCall system is proposed, comprising a generator configured to provide an initial data code and an interface for providing an initial audio signal, and a wireless secondary communication module that is signal-coupled to the generator and the interface. The secondary communication module can be configured to transmit the initial audio signal and / or the initial data code to an emergency call unit as described above. Furthermore, the communication module can be configured to receive audio signals and / or a secondary data code from the emergency call unit.Additionally, the emergency call service facility may include a verification unit which is configured to compare the first data code with the second data code in order to verify an electroacoustic communication loop to and from the emergency call unit by means of a result of the comparison, wherein in particular the electroacoustic communication loop includes an acoustic path between a transducer and a microphone of the emergency call unit.

[0050] According to one aspect, it is proposed that the emergency service facility be equipped with an authentication unit to authenticate data, in particular a second data code, received from the emergency call unit via the second communication module. The signature code, digital signature, and / or digital certificate may be asymmetrically encrypted.

[0051] An emergency call system is proposed, comprising an emergency service facility as described above and an emergency call unit as described above. The emergency call system is configured to test an electroacoustic communication loop between the emergency service facility and the emergency call unit, wherein the electroacoustic communication loop specifically includes an acoustic path between a transducer and a microphone of the emergency call unit.

[0052] A vehicle is proposed which includes an emergency call unit as described above, in particular to communicate with an emergency service facility in the event of an emergency.

[0053] For further clarification, the invention is described with reference to embodiments illustrated in the figures. These embodiments are to be understood as examples only, and not as limitations.

[0054] Brief description of the characters

[0055] This shows:

[0056] Fig. 1 shows a block diagram of an emergency call unit and a coupled emergency service facility; and

[0057] Fig. 2 shows a block diagram of an emergency call service facility.

[0058] Detailed description of embodiments

[0059] In the figures, identical reference symbols denote either identical elements or elements with equivalent functions. Elements that have already been described are not necessarily described again in subsequent figures.

[0060] Figure 1 schematically shows a block diagram of an emergency call unit 100, which is set up to be wirelessly coupled with an emergency service facility 200, for example by means of a mobile network 400, in order to exchange network signals R with each other.

[0061] The emergency call unit 100 can be used, for example, for an eCall system and includes an input interface 170 for audio signals, which is set up to be coupled with a microphone 102 and an output interface 150 for outputting audio signals, which is set up to be coupled with a sound-generating transducer 101, such as a loudspeaker.

[0062] Furthermore, the emergency call unit 100 includes a modulation device 120, which is set up to modulate an original audio signal Xr by means of a first data code Ds and to provide a resulting modulated audio signal Xa to the output interface 150 in order to generate a transmitted sound signal Xn for an acoustic path A between the sound transducer 101 and the microphone 102 by means of the sound generating transducer 101.

[0063] Furthermore, the emergency call unit 100 includes a demodulation device 130, which is set up to demodulate a microphone signal Yn induced by the emitted sound signal Xn and generated by means of the microphone 102 on the acoustic path A, which can be provided at the input interface 170 as a generated audio signal Ym, in order to determine a second data code Dt, based on the modulation of the generated audio signal Ym.

[0064] This means that the generated audio signal Ym can be modulated with the second data code Dt.

[0065] For example, the demodulation device 130 can be set up to determine the second data code Dt, based on the generated audio signal Ym and the original audio signal Xr.

[0066] The demodulation unit 130 can be coupled to the input interface 170 to access the provided generated microphone signal Ym. Additionally, the demodulation unit 130 can be coupled to the first communication module 110 to access the provided original audio signal Xr. The emergency call unit 100 can be configured, in particular by means of a function of the demodulation unit 130, and / or the emergency service unit 200 can be configured to verify an acoustic path A, in particular a functionally established acoustic path A, between the transducer 101 and the microphone 102 by comparing the first data code Ds with the second data code Dt.

[0067] The original signal Xr and the first data code Ds can alternatively or additionally be stored in a memory area of ​​the emergency call unit 100. This allows the emergency call unit 100 to be configured to check an acoustic path A between a transducer 101 and a microphone 102 of the emergency call unit 100, particularly periodically.

[0068] Alternatively or additionally, the emergency call unit 100 can be set up to transfer the second data code Dt to the emergency service unit 200.

[0069] The emergency call unit 100 may include an emergency detection unit 160, which is set up to detect an emergency and / or accident.

[0070] By means of a wireless first communication module 110, which is signal-coupled with the emergency detection unit 160, the emergency call unit 100 can be set up to communicate with the emergency service facility 200.

[0071] The first communication module 110 can be coupled with the modulation device 120 and configured to provide the first data code Ds and / or an initial audio signal Xr to the modulation device 120. The first communication module 110 can also be configured to receive the first data code Ds and / or the initial audio signal Xr from the emergency service device 200.

[0072] The emergency call unit 100 can be configured, in the event of an emergency and / or accident detected by the emergency detection unit 160, to establish a signal link between the emergency call unit 100, in particular via the wireless first communication module 110, and the emergency service unit 200, so that the emergency service unit 200 can provide the initial audio signal Xr and the first data code Ds to the first communication module 110. The emergency call unit 100 can also be configured to provide emergency information C, determined and / or stored by the emergency call unit 100, to the first communication module 110 for transfer to the emergency service unit 200.

[0073] By means of a signal coupling of the demodulation device 130 with the emergency detection unit 160 and a signal coupling of the emergency detection unit 160 with the first communication module 110, the emergency call unit 100 can be set up, by means of wireless coupling with the emergency service device 200, to provide the emergency service device 200 with the second data code Dt, so that the emergency service device 200 can check an electroacoustic communication loop to and from the emergency service device 200, in particular including the acoustic path A between the transducer 101 and the microphone 102.

[0074] The input interface 170 can be configured to be coupled to multiple microphones and, in particular, to superimpose the respective signals of the multiple microphones as a single overall signal, especially in the event of a detected emergency. Additionally or alternatively, the input interface 170 can be equipped with a beamforming module and configured to use the multiple microphones to determine the position of acoustic signal sources in order to improve the transmission of audio signals from the input interface to the emergency service unit 200 and / or to superimpose the respective signals of the multiple microphones as a single overall signal.Additionally or alternatively, the input interface 170 can be equipped with a filter module and configured to perform frequency filtering of audio signals from at least one microphone in order to improve the transmission of audio signals from the input interface to the emergency service facility 200.

[0075] The emergency call unit 100 can include a signal processing module 140, which is coupled to the input interface 170 and the first communication module 110, in particular to transmit an audio signal from the input interface 170 to the emergency service unit 200. The signal processing module 140 can be configured to remove the modulated audio signal Xa from the generated audio signals Ym provided by the input interface 170 before the audio signals provided by the input interface 170 are transmitted as signals Yr to the emergency service unit 200, in particular to reduce disruptive echoes and / or feedback.Alternatively, the original audio signal Xr can also be used as a reference signal to eliminate it from the signal Ym. However, this has the disadvantage that the modulation fluctuations applied by the modulation device cannot be compensated for and may possibly lead to interference in the emergency service facility, especially in an existing hands-free device.

[0076] Emergency call unit 100 can be configured to provide and / or generate a digital certificate Z1. The demodulation unit 130 of emergency call unit 100 can be configured to transfer the second data code Dt, certified by digital certificate Z1, to emergency service unit 200, so that emergency service unit 200 can authenticate the certified second data code Dt, K of emergency unit 100 by means of a certificate verification Z2.

[0077] Figure 2 schematically shows a block diagram of an emergency service device 200, which is configured to be wirelessly coupled with an emergency call unit 100, for example via a mobile network 400, in order to transmit network signals R bidirectionally. The emergency service device 200 comprises a generator 220, which is configured to provide a first data code Ds, a communication input interface 250 for providing an initial audio signal Xr, and a wireless second communication module 210, which is signal-coupled to the generator 220 and the communication input interface 250. The initial audio signal Xr can be generated as an audio signal Xs by an operator of the emergency service device 200 and provided to the communication input interface 250 by means of a signal-coupled microphone 202.

[0078] The second communication module 210 is configured to be wirelessly paired with an emergency call unit 100, as described above, in particular to transmit the original audio signal Xr and / or the first data code Ds, each of which may be part of the network signal R, to the emergency call unit 100. Additionally, the second communication module 210 is configured to receive an audio signal Yr and / or a second data code Dt, each of which may be part of the network signal R, from the emergency call unit 100 and to make them available to the emergency service unit 200.

[0079] Furthermore, the emergency service unit 200 comprises a verification unit 230, which is signal-coupled to the second communication module 210 and the generator 220. The verification unit 230 is configured to compare the first data code Ds, generated in particular by the emergency service unit 200, with the second data code Dt, transmitted wirelessly by the emergency call unit 100, in order to verify a communication loop from the emergency service unit 200 to the emergency call unit 100 and from the emergency call unit 100 to the emergency service unit 200 using the result E of this comparison. In particular, an electroacoustic path of the communication loop includes an acoustic path A between a transducer 101 and a microphone 102 of the emergency call unit 100, such that the functionally constructed electroacoustic path also verifies the functionally constructed acoustic path A.The emergency service facility 200 can be configured to specifically authenticate, in particular by means of a certificate verification Z2, a second data code Dt of the emergency call unit received by the emergency call unit 100 by means of the second communication module 210 and certified by means of a digital certificate Z1, by means of an authentication unit which can be part of the verification unit 230.

[0080] The emergency service unit 200 can have a communication screen interface 240, which is coupled to the second communication module 210 and / or the verification unit 230, in particular to provide a signal B. The communication screen interface 240 can be configured to provide the result E of the comparison and / or emergency call information C to a connected screen 204, and thereby in particular to the operator of the emergency service unit 200.

[0081] The emergency service facility 200 can have a communication audio interface 260, which is coupled to the second communication module 210, in order to provide audio signals Yr, which the second communication module 210 provides, to a coupled emergency service transducer 201 as audio signal Ys, and thereby in particular to an operator of the emergency service facility 200.

[0082] Reference symbol list

[0083] 100 emergency call unit

[0084] 101 Sound-generating transducer

[0085] 102 Microphone for the emergency call unit

[0086] 110 first communication module

[0087] 120 Modulation unit

[0088] 130 Demodulation unit

[0089] 140 Signal processing module

[0090] 150 output interface

[0091] 160 Emergency Detection Unit

[0092] 170 Input interface

[0093] 200 emergency call service facility

[0094] 201 Emergency Service Transducers

[0095] 202 Microphone of the emergency service facility

[0096] 203 Emergency Call Operator

[0097] 204 Monitor for the emergency service facility

[0098] 210 second communication module

[0099] 220 Generator

[0100] 230 verification units

[0101] 240 Communication Screen Interface

[0102] 250 Communication input interface

[0103] 400 wireless communication system

[0104] An acoustic path

[0105] B Communication monitor connection

[0106] C Emergency Information

[0107] The first data code

[0108] German second data code

[0109] E result

[0110] K Signature Code

[0111] R network signal

[0112] Z1 Certificate

[0113] Z2 certificate verification Xa modulated output signal

[0114] Xn emitted sound signal

[0115] XR original audio signal

[0116] Xs sound signal from a microphone of the emergency service facility Ym generated audio signal

[0117] Ys sound signal from a sound transducer of an emergency service facility

[0118] Yr Audio signal for a sound transducer of an emergency service facility

Claims

Patent claims 1. Emergency call unit (100) for an eCall system, comprising: an input interface (170) for audio signals, configured to be coupled with a microphone (102); an output interface (150) for outputting audio signals, configured to be coupled with a sound-generating transducer (101); a modulation device (120), configured to modulate an original audio signal (Xr) by means of a first data code (Ds) and to provide a resulting modulated audio signal (Xa) to the output interface (150) in order to generate a transmitted sound signal (Xn) by means of the sound-generating transducer (101); and a demodulation device (130) which is configured to demodulate an audio signal (Yn) induced by the emitted sound signal (Xn) and generated by means of the microphone, which is provided at the input interface (170) in order to determine a second data code (Dt);wherein the emergency call unit (100) and / or a signal-coupled emergency service device (200) is set up, to check an acoustic path (A) between the transducer (101) and the microphone (102) by comparing the first data code (Ds) with the second data code (Dt).

2. Emergency call unit (100) according to claim 1, wherein the modulation device (120) is configured to modulate the original audio signal (Xr), in particular by means of a selection of the first data code (Ds); and / or a selection of a modulation method; and / or by means of a magnitude of a modulation amplitude; and / or by means of a modulation frequency, such that the modulation of the original audio signal (Xr) is not disturbing to a human listener; and / or in particular, the intelligibility of the modulated audio signal (Xa) is not reduced compared to the original audio signal; and / or, particularly advantageously, a difference between the modulated audio signal (Xa) and the original audio signal (Xr) is below an acoustic perception threshold of human hearing.

3. Emergency call unit (100) according to claim 1 or 2, wherein the modulation device (120) is configured to modulate the original audio signal (Xr) such that the second data code (Dt) can be determined by means of a power spectrum of the modulated audio signal (Xa).

4. Emergency call unit (100) according to claim 1, wherein the emergency call unit (100) is configured to decouple the modulation device (120) from the demodulation device (130), in particular with respect to the first data code (Ds) and / or the second data code (Dt), in order to preferably certify the emergency call unit (100) as safe with respect to its functionality.

5. Emergency call unit (100) according to one of the preceding claims, which is configured to provide the original audio signal (Xr) and / or the first data code (Ds) in order to check the acoustic path (A) between the sound transducer (101) and the microphone (102), in particular periodically and / or externally triggered, by comparing the first data code (Ds) with the second data code (Dt).

6. Emergency call unit (100) according to one of the preceding claims, comprising: a wireless first communication module (110) for communicating with an emergency call service unit (200); wherein the original audio signal (Xr) is provided by the emergency call service unit (200); and / or wherein the first data code (Ds) is provided by the emergency call service unit (200); and wherein the emergency call unit (100) is configured to transmit the second data code (Dt) of the emergency call service unit (200) by means of the wireless communication module (110) in order to establish an electroacoustic communication loop to and from the emergency call service unit (200), in particular including the acoustic to have the path (A) between the transducer (101) and the microphone (102) checked by the emergency call service facility (200).

7. Emergency call unit (100) according to claim 6, which is set up, - to provide and / or generate a signature code and / or a digital signature and / or a digital certificate (Z1); and - to transfer the second data code (Dt) certified with the signature code and / or digital signature and / or digital certificate to the emergency call service facility (200) in order to authenticate the second data code (Dt) of the emergency call unit (100) based on the signature code and / or digital signature and / or digital certificate (Z1).

8. Emergency call unit (100) according to claim 6 or 7, which is configured to transmit audio signals provided by the input interface (170) to the emergency service facility (200) by means of the wireless first communication module (110); and wherein, in particular, the emergency call unit (100) has a signal conditioning module (140) which is configured to remove the modulated audio signal (Xa) from the audio signals (Ym) provided by the input interface (170) before the provided audio signals are transmitted to the emergency service facility (200).

9. Emergency call unit (100) according to any one of claims 6 to 8, comprising: an emergency detection unit (160) which is configured, in particular by means of a signal coupling with an accelerometer; and / or a camera; and / or a bodily function sensor; and / or a manually operated trigger, to detect an emergency and / or accident; and wherein the emergency call unit (100) is configured, in the event of a detected emergency and / or accident, to transmit audio signals provided by the input interface (170) to the emergency call service device (200) by means of the wireless first communication module (110).

10. Emergency call unit (100) according to one of the preceding claims, wherein the input interface (170) is configured to be coupled to a plurality of microphones via signals, and in particular to provide the respective signals of the plurality of microphones superimposed as a total signal.

11. Emergency call unit (100) according to claim 10 and one of claims 6 to 9, wherein the input interface (170) has a beamforming module which is configured to determine the position of sources of acoustic signals with the plurality of microphones in order to improve the transmission of audio signals from the input interface (170) to the emergency service unit (200) and / or to provide the respective signals of the plurality of microphones superimposed as a total signal.

12. Emergency call unit (100) according to claim 10 and one of claims 6 to 9, or 11, wherein the input interface (170) has a filter module to improve the transmission of audio signals from the input interface (170) to the emergency service facility (200) by means of frequency filtering of audio signals from at least one microphone (102).

13. Emergency service device (200) for an eCall system, comprising: a generator (220) configured to provide a first data code (Ds); a communication interface (250) for providing an initial audio signal (Xr); a wireless second communication module (210) signal-coupled to the generator (220) and the communication interface (240); wherein the second communication module (210) is configured to transmit the initial audio signal (Xr) and / or the first data code (Ds) to an emergency call unit (100) according to any one of claims 1 to 12; and further configured to receive audio signals and / or a second data code (Dt) from the emergency call unit (100); a verification unit (230) configured to compare the first data code (Ds) with the second data code (Dt) in order to verify the identity of the first data code (Ds) by means of a The result (E) of the comparison is to test an electroacoustic communication loop to and from the emergency call unit (100), wherein in particular the electroacoustic communication loop includes an acoustic path (A) between a sound transducer (101) and a microphone (102) of the emergency call unit.

14. Emergency service facility (200) according to claim 13, which is equipped by means of an authentication unit, to authenticate a signature code and / or a digital signature and / or a digital certificate data, in particular a second data code, received by means of the second communication module (210) from the emergency call unit (100).

15. Emergency call system comprising: an emergency call service device (200) according to claim 13 or 14; an emergency call unit (100) according to any one of claims 1 to 12; wherein the emergency call system is configured to test an electroacoustic communication loop between the emergency call service device (200) and the emergency call unit (100), and wherein in particular the electroacoustic communication loop includes an acoustic path (A) between a transducer (101) and a microphone (102) of the emergency call unit (100).

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