CA2085959A1 - Method of common transfer of digital, audio and control data on a common bus line; bus system for implementing the method and interface for application in the method - Google Patents
Method of common transfer of digital, audio and control data on a common bus line; bus system for implementing the method and interface for application in the methodInfo
- Publication number
- CA2085959A1 CA2085959A1 CA002085959A CA2085959A CA2085959A1 CA 2085959 A1 CA2085959 A1 CA 2085959A1 CA 002085959 A CA002085959 A CA 002085959A CA 2085959 A CA2085959 A CA 2085959A CA 2085959 A1 CA2085959 A1 CA 2085959A1
- Authority
- CA
- Canada
- Prior art keywords
- interface
- data
- user
- control data
- fiber optic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/20—Circuits for coupling gramophone pick-up, recorder output, or microphone to receiver
- H04B1/205—Circuits for coupling gramophone pick-up, recorder output, or microphone to receiver with control bus for exchanging commands between units
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
- B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
- B60R16/03—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for
- B60R16/0315—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for using multiplexing techniques
Abstract
Abstract A bus system for the transfer of audio and control data on a common bus line of fiber optic cables (LWL) in a system of users is compatible with sources and sinks of audio data (2,2a,2b) and/or control and monitoring data (8,8a,8b). Bach user is connected to the bus system by a standardized interface (5,6a,6b) circuited together in series via fiber optic cables (LWL A, LWL B) preferably closed to form a ring by means of a further fiber optic cable (LWL C). This bus system is suitable for being operated with an internationally standardized transfer format. The bus system is impervious to noise, can be produced at low cost and is exceptionally powerful. This bus system is particularly suitable for use in vehicles.
Fig. 1
Fig. 1
Description
208~9S9 ,.`' "~.- ~" .' .
Method of Common Transfer of Digital, Audio and Control Data on a Common Bus Line; Bus System for Implementing the Method and Interface for Application in the Method ,, -,.",,',.
The invention relates to a method of common transfer of digital audio and control data on a common bus line in a user system to which at least one digital audio source and at least one digital control data signal source belong; a bus system for implementing the method and an interface for application in the method. :.
In many fields of engineering a local conglomeration of completely different kinds of electrical and electronic equipment is required :~
to exchange information which thus requires networking in a sometimes complicated manner. For instance, in m~tor vehicles, sources of audio signals such as radio receivers, casse~te : ;~
~ ~`'"''`.`
- ':
:
, 2 0 ~ 5 9 ~ 9 recorders or CD players require, on the one hand, connecting together and, on the other, to audio sinks such as amplifier speaker combinations. It may prove useful to also incorporate audio equipment which formerly fonmed a separate system, such as car phones in such a system. In addition, there is a trend towards increasingly complex control and monitoring of vehicle functions. Of the innumerable possibilities in this respect, here merely monitoring the function of external lights on the vehicle or the inflation pressure or measuring and/or controlling the engine speed -~
or the turbocharging pressure is cited.
For this purpose extensive wiring connections are necessary between the individual components. Even when, as intended, many items of equipment and functions are controlled and handled by a vehicle computer, the problem of the many wires and the length thereof remains. Also of disadvantage is the fact that many of the known -components are unable to directly communicate with each other. For instance, to prompt the audio system to output a recorded text as a warning via the speakers, in the case of a reduction in tyre inflation pressure, the expense involved until now was prohibitive.
A great many other examples of networking vehicle components have already been stated which, however, have only been realized in part, such as a standardi2ed transfer of audio data, on the one hand, or control data, on the other, each via a separate network of shielded wiring. Employing a bus system, although desirable, is hampered by major difficulties as regards the necessary bus arbitration and the resulting time losses. Since users of the most different kinds have to be connected to the common bus line which is required to handle a data thruput, to transfer two-channel digital audio data in addition to control and measurement data, for example, conflicting transfer requirements can hardly be avoided. m~
.. ~ .
~3-208~9~9 :~
The object forming the basis of the invention i91 to achieve a universal system for the exchange of audio and control data between many and varied items of electrical and electronic equipment via a bus system which is reliable, cost-ef~ective ancl exceptionally powerful.
This object - as far as the method is concerned - is achieved by the features of claim 1 of the invention. The features of a bus system suitable for implementing the method according to the invention as well as a corresponding hardware interface are disclosed by claLms 5 ; ~ ;
and 8. ~
., The achievement according to the invention offers a wealth of advantages. By all items of equipment to be connected to each other being circuited in series by a single bus line, wiring can be saved and the circuiting simplified. Using fiber optic cables for data -transfer achieves, on the one hand, complete freedom from noise whilst, on the other, greatly reducing weight and saving material which in vehicle applications involving the use of very many electrical and electronic components is particularly significant. ~;
Diqital transfer places only minor requirements on the quality of the optical transfer medium and the electrooptical conver~ers used and thus the costs thereof are slight. Since the transfer distances involved are short, low-cost plastic fiber optic cables can be employed. Due to the interfaces permitting standardization allowing ~-the same type of interface module to be used, the electronics can also be realized at low cost~ This eliminates complicated bus arbitration since each user has its own transmit channel and control ~ ;
data can be transferred monodirectional on each section of the fiber optic cable. This channel dedication permits optimum use to be made of available user channel capacity, since no capacity whatsoever must be reserved for bus arbitration. Apart from this, channel ~ ~.
: .:
208~959 ....
dedication permits exceptionally straight-forward user software coupling.
In the preferred embodiment of the bus system the series circuit of the users is a closed ring according to claim lt). Receiving control data can then be acknowledged according to clai~ 3 by a specific bit in the signal sequence being modified or removed. since the modified signal sequence is returned to the transmitting interface via the closed ring bus system, this interface is directly informed whether its assigned control data channel is again available.
In accordance with claim 3 the AES3-1985 standard is used as the transfer format. This standard was created in coordination with the -,. . . . . .
European Broadcasting Union as an internationally standardized protocol for digital audio transfer which is already used in ~ `
conjunction with CD players and makes a single data channel available to the user which can be employed to transfer control data, for example. The fact that only a single data channel is available shows that this format is not actually intended for use in a bus system. The bus system according to the invention suffices with a signal channel due to the time multiplexing on the bus line.
Apart from this, there is no problem in operating the bus system according to the invention with its own standard; however, using an international protocol facilitates communication with users such as CD equipment, using this pro~ocol.
The remaining subclaims relate to further advantageous embodiments of the invention.
The invention is not only suitable for application in automobiles but also in particular in aerospace vehicles due to the low weight ~-of the data transfer circuitry. In addition, networking stationary video, audio, telephone and data processing systems is also possible 2 0 8 ~ 9 5 9 by means of the bus system according to the invention to reduce the volume of the circuit connections formerly neceC~sary.
Further features and advantages of the invention result ~rom the following description of several embodiments ancl with reference to the drawing in which~
ig. 1 is a schematic diagram showing a system of users employing the method of the invention, ig. 2 serves to explain the data transfer formats used in the method r .,, ~.. :.
Fig. 3 illustrates the multiplexing step of the method, Fig. 4 shows a data sequence in a control data channel, ig. 5 is a schematic diagram showing how one of the interfaces is equipped for selecting the various audio sources, and Fig. 6 serves to explain the configuration and function of an ~ -interface between fiber optic cable sections and a system user.
In the embodiment shown in Fig. 1 an audio source 2, such as a radio receiver, for example, presents its audio signal to an input circuit 4 of an interface 6. The input circuit 4 for instance, can be one of the known circuits 12S, Sony bus or MSB-LSB-First having a variable format length. The audio source 2 is further connected to a control unit 8 which outputs certain control signals, for example, control ~
signals which determine which of several loudspeakers is to be ~ ;
signalled. These control signals are applied to interface 6 via a , ,' ~' ~` ' '.' . ~ ;-,"`` -~
~
:
-20859~9 suitable parallel or serial interface 10 of the latter where they ~ ;
are converted together with the audio data into a common serial data format which is described in more detail below and features a data channel for the control signals. Should no such control signals be available at interface 6, due to the radio receiver ~ailing to have such options, for example, the bits representing the control signals -~
are set to zero. The data clock is determined by the clock of the audio data stemming from the audio source 2, when it sends the data -in a suitable data format or by means 12 comprising a clock source and data buffer belongin~ to the interface. The data clock frequency is 32.0, 44.1 or 48.0 kHz, for example, corresponding to a baud rate of 2.0, 2.8 and 3.0 Mbaud respectively.
The seguence of audio and control data in common is converted by an -~
electrooptical converter 14 into a synchronous light signal which is applied to a fiber optic cable section LWL A. This embodiment is intended for a relatively compact system so that low-cost plastic fiber optic cables and converters of the simplest kind can be used.
Fiber optic cables of plastic can also be circuited with very small - -radii of curvature which is of a great advantage in an autombile, for example. The fiber optic cable section LWL A ends in an optoelectrical converter 16 of a second interface 6a which has an ~ ~
identical configuration to that of the interface 6 and which ~ -connects an audio processor 2a. The latter may be, for e~ample, a multi-channel bass/treble control. The audio data is made available to the audio processor 2a via a suitable output circuit 18 where the data is modified, as required, and returned to the interface 6a. In this embodiment the audio processor 2a also features a control unit 8a which is able to ~eact to control data contained in the data sequence and output by a suitable interface lOa or which is able to --output control data itself. - -:
'` ',' : :~ ", 2 0 ~ ~ 9 5 9 ~
The same as in the first interface 6, here too ~he data, which may be modified where necessary, are then applied to a second fiber optic cable section LWL ~ for monodirectional entry into a third ~ -~
interface 6b, again having the same configuration as that of interface 6, by means of which the data activates an audio sink 2b such as, for instance, an amplifier/speaker combination via which the audio signals are to be reproduced acoustically. The audio sink ~ ~
2b comprises a control unit 8b for receiving data from the control ~ `
data channel.
All interfaces 6, 6a and 6b have an identical configuration to rationalize their production; however, it is not always the case that they are used in their entirety.
Another feasible arrangement would be that the control unit 8b belonging to the audio sink 2b has a control data output to prompt corrections of the bass/treble control, should, for instance a speaker failure occur. It is good practice not only in this case to connect the third interface 6b via a third fiber optic cable section LWL C to the first interface 6 as is indicated by the dashed line in Fig. 1. Such a ring arrangement of users is, in fact, a preferred embodiment of the invention and is described in more detail below.
Fig. 2 shows the smallest unit 20 of the data format preferably used in view of the intended maximum-possible compatibility in accordance with the AES-EBU protocol for audio transfer in the consumer range and professional studio range AES3-1985 ( ANSI S4.40-1985, Standards and Information Documents, Audio Engineering Society, Inc., New York 1985). This unit 20 is termed a subframe and contains 32 bits. A
first group 22 of 4 bits in the unit 20 serves to synchronize and distinguish between the left-hand and right-hand stereo channel. A
second group 24 of 8 bits following in time sequence is available for audio data which is, however, still hardly made use of -~-~ ,, ':
2 0 8 5 9 5 .~
currently. This is followed by a third group 26 of 16 bits for audio data which is already used. The termination o~ a subframe 20 is formed by a sequence of discrete bits 28, 30, 32 and 34 of which bit 30 is termed the user bit and can be utilized by the user arbitrarily without affecting audio transfer. A~ regards the significance of the bits 28, 32 and 34 reference is made to the cited AES-EBU protocol. Each stereo channel is assigned a subframe 20, two of which follow in sequence in each case to form a frame, 192 frames then forming what is termed a block.
The user bit 30 causes a serial data channel to be opened which is subdivided into any number of subchannels by a time multiplex procedure. Fig. 3 shows, for example, the divisioning into 10 subchannels. Each 1st, 11th, 21st etc bit of the data sequence contained in the data channel opened by the user bit 30 is assigned as a subchannel to a channel 1, each 2nd, 22nd, 32nd etc bit to a channel 2, and so on. Each user transmits on a channel. For a total baud rate of 2 Mbaud a control data baud rate of 64 kbaud results for a 32 bit long subframe 20. In a preferred embodiment 8 subchannels are provided for each of which a transfer capacity of 8 kbaud thus remains, such a capacity being sufficient to transfer even complex infonmation.
Fig. 4 shows a special data sequence in one of the 8 user channels of four blocks n, n+1, n+2 and n+3, each 48 bits long ~384 -subframes/8 subchannels~. Each block bgsins with a bit 40 set to logical 1 to mark the start of the data sequence. This is followed by a start bit 42, this being set to logical 1 on commencement of the data message to be transferred and to logical 0 when the data message is continued with the next block. The start bit is followed by a 7 bit long address 44, each user being assigned a specific f address. The address 44 is followed by a bit 46 which the -~
,,~,," ,........
2~859~9 receiver of a data sequence can change to acknowledge receipt or inform the sender whether a channel is again vacant or whether the message was rejected. Bit 46 is followed by a bit sequence 48 containing coded information as to the length oi~ the subsequent actual data sequence. This data is transferred ln groups 50, identified in Fig. 4 by Datal, Data2, etc.
Fig. 5 is a schematic diagram showing how two further audio sources Auxl and Aux2 are coupled to the bus system via an interface 6. The configuration of interface 6 corresponds to that of the interfaces 6, 6a and 6b shown in Fig. 1. The selectors 52 and 54 which may also be implemented electronically permit the choice of signal feed from the audio sources Auxl and Aux2. In the special case in which the selectors 52 and 54 are both in the UP position in Fig. 5 the audio signals of the bus system pass the interface 6 unchanged.
The salient parts of one of the interfaces 6, 6a or 6b shown in Fig.
1 are depicted in the block diagram of Fig. 6. Parts which have already been explained in conjunction with Fig. 1 have received the same reference numerals. All parts with the exception of the electrooptical convertors 14 and 16 are implemented in a single ;
integrated circuit to save costs. The converters 14 and 16 are here considered as elements of the interface, but ln actual implementation can be connected right from the start with the fiber optic cables and are not connected electrically to the remaining -~
parts of the interface until the system is installed. A circuit 60 contains a phase locked loop PLL which tunes itself to the electrical signals coming from the one converter 16. Circuit 60 is also capable of determining when an address contained in the signals ;
agrees with an address assigned to the corresponding interface. In addition, the data sequence is applied to the receiver buffer 62.
The audio data is converted via an output circuit 18 into various ..... - . ~
-.`'.`'`'`'`'`'`,`".-2 ~ ~ 5 9 ~ 9 formats of which the one matching a respective connected audio unitis transferred. Control data is applied to a microprocessor of the connected user and back again via an interface 10 also designed to handle several formats. The control data to be t:ransmitted is applied via a transmit buffer 64 tO a multiplexing means 66, the `~
mentioned format being configured, on the one hcmd, and, on the other, the control data being read into the multiple~ channel correct in time. Audio data arri~ing from the connected audio unit via an input circuit 4, or, audio data from the receiver buffer 62 are also incorporated in the format and the complete data sequence is applied to a converter 14 which converts the electrical signals back into optical signals. Data management is the job of a control and status register 68 connected to the receiver buffer 62, the transmit buffer 64 and the interface 10. When an address contained in the data fails to agree with the user address the data is passed on unchanged. Due to buffering a certain shift in time results, this being arranged, however, so that the data is resorted into its correct channel. The clock information is received by the transmit buffer 64 from a clock circuit 70 which receives the clock either ~ -~
from the PLL circuit 60 or from a separate clock generator. This clock generator need not be a component of the interface, however, since commercially available audio sources such as CD players generally contain such a clock generator, this being the reason why it is not indicated.
As evident from Fig. 1 a basic distinction is made among three different modes of opPration as regards audio transfer. The mode of the interface 6 shown on the left in the Fig. is an active mode in ~;-which the mentioned data format is originally generated, i.e. based ~-either on the clock of the data stemminq from the audio source 2 or -~ -on the clock of a separate clock generator. In this so-called master mode only one interface of a system is ~ ~
.: ,~ '~`''.-.''.''.' - . , - .: - .
~ ~ .
--ll--208~959 operative at any one time. The two other interfaces 6a and 6b generate no clock of their own, but adapt by the!ir PLL circuit to the clock as specified. This mode of operation is termed slave mode.
Interface 6a shown in the middle of the Fig. ha a special feature, it being able to receive and also modify audio data when required.
In this case the mode i5 termed a slave/processor mode. The interface 6b on the right of the Fig. behaves purely passive as regards the audio data by it merely passing the data on.
An essential feature of the invention is that data transfer via the fiber optic cables is in one direction only. Only one user operates in the master mode and thus dictates the cl w k. Together with the fact that each user employs its own transmit channel and a bus arbitration is not necessary it is possible to connect a large number of users to a single network without transfer conflict -~
despite a high data thruput. Transmitting is possible on all control data channels at the same time, this being the reason why each control data channel has a mean data transfer rate which is available at all times. Compared to conventional bus systems of comparable performance the costs of realizing the system are exceptionally low. Nhen the first and last user are reconnected together a closed ring results in which a message can circulate until its receiver accepts it. The sender of a message is able to ;~
determine whether its message has arrived at the receiver. To this end, bit 46 is used which as already mentioned in conjun~tion with Fig. 4 is altered or removed by the receiver of a message to -~
acknowledge the receipt. -~
In one particular embodiment of the invention the audio data is rerouted already within the interface and directly retransmitted, namely when the connected user features no audio unit at all or merely executes control or monitoring functions.For instance, - ~ , ' `. '''`~ " ~.'~' , ' `- ~ ~' `' ' '`'`' '`'~;~,'` ` ' ` ' `' -, . ~-.
-12~
2085~59 the system can be used with any of the many types of sensors employed in a vehicle. In one embodiment of the invention these sensors can be interrogated within the scope of a vehicle diagnosis for which a separate diagnosis subchannel is prc~vided by means of a :~
transparent bit which is not manipulated and passes through the ~-chain of users without being changed.
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~. ~''".',.~
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'.~' :,, -.
: : -: .:
,. . ~ : .
Method of Common Transfer of Digital, Audio and Control Data on a Common Bus Line; Bus System for Implementing the Method and Interface for Application in the Method ,, -,.",,',.
The invention relates to a method of common transfer of digital audio and control data on a common bus line in a user system to which at least one digital audio source and at least one digital control data signal source belong; a bus system for implementing the method and an interface for application in the method. :.
In many fields of engineering a local conglomeration of completely different kinds of electrical and electronic equipment is required :~
to exchange information which thus requires networking in a sometimes complicated manner. For instance, in m~tor vehicles, sources of audio signals such as radio receivers, casse~te : ;~
~ ~`'"''`.`
- ':
:
, 2 0 ~ 5 9 ~ 9 recorders or CD players require, on the one hand, connecting together and, on the other, to audio sinks such as amplifier speaker combinations. It may prove useful to also incorporate audio equipment which formerly fonmed a separate system, such as car phones in such a system. In addition, there is a trend towards increasingly complex control and monitoring of vehicle functions. Of the innumerable possibilities in this respect, here merely monitoring the function of external lights on the vehicle or the inflation pressure or measuring and/or controlling the engine speed -~
or the turbocharging pressure is cited.
For this purpose extensive wiring connections are necessary between the individual components. Even when, as intended, many items of equipment and functions are controlled and handled by a vehicle computer, the problem of the many wires and the length thereof remains. Also of disadvantage is the fact that many of the known -components are unable to directly communicate with each other. For instance, to prompt the audio system to output a recorded text as a warning via the speakers, in the case of a reduction in tyre inflation pressure, the expense involved until now was prohibitive.
A great many other examples of networking vehicle components have already been stated which, however, have only been realized in part, such as a standardi2ed transfer of audio data, on the one hand, or control data, on the other, each via a separate network of shielded wiring. Employing a bus system, although desirable, is hampered by major difficulties as regards the necessary bus arbitration and the resulting time losses. Since users of the most different kinds have to be connected to the common bus line which is required to handle a data thruput, to transfer two-channel digital audio data in addition to control and measurement data, for example, conflicting transfer requirements can hardly be avoided. m~
.. ~ .
~3-208~9~9 :~
The object forming the basis of the invention i91 to achieve a universal system for the exchange of audio and control data between many and varied items of electrical and electronic equipment via a bus system which is reliable, cost-ef~ective ancl exceptionally powerful.
This object - as far as the method is concerned - is achieved by the features of claim 1 of the invention. The features of a bus system suitable for implementing the method according to the invention as well as a corresponding hardware interface are disclosed by claLms 5 ; ~ ;
and 8. ~
., The achievement according to the invention offers a wealth of advantages. By all items of equipment to be connected to each other being circuited in series by a single bus line, wiring can be saved and the circuiting simplified. Using fiber optic cables for data -transfer achieves, on the one hand, complete freedom from noise whilst, on the other, greatly reducing weight and saving material which in vehicle applications involving the use of very many electrical and electronic components is particularly significant. ~;
Diqital transfer places only minor requirements on the quality of the optical transfer medium and the electrooptical conver~ers used and thus the costs thereof are slight. Since the transfer distances involved are short, low-cost plastic fiber optic cables can be employed. Due to the interfaces permitting standardization allowing ~-the same type of interface module to be used, the electronics can also be realized at low cost~ This eliminates complicated bus arbitration since each user has its own transmit channel and control ~ ;
data can be transferred monodirectional on each section of the fiber optic cable. This channel dedication permits optimum use to be made of available user channel capacity, since no capacity whatsoever must be reserved for bus arbitration. Apart from this, channel ~ ~.
: .:
208~959 ....
dedication permits exceptionally straight-forward user software coupling.
In the preferred embodiment of the bus system the series circuit of the users is a closed ring according to claim lt). Receiving control data can then be acknowledged according to clai~ 3 by a specific bit in the signal sequence being modified or removed. since the modified signal sequence is returned to the transmitting interface via the closed ring bus system, this interface is directly informed whether its assigned control data channel is again available.
In accordance with claim 3 the AES3-1985 standard is used as the transfer format. This standard was created in coordination with the -,. . . . . .
European Broadcasting Union as an internationally standardized protocol for digital audio transfer which is already used in ~ `
conjunction with CD players and makes a single data channel available to the user which can be employed to transfer control data, for example. The fact that only a single data channel is available shows that this format is not actually intended for use in a bus system. The bus system according to the invention suffices with a signal channel due to the time multiplexing on the bus line.
Apart from this, there is no problem in operating the bus system according to the invention with its own standard; however, using an international protocol facilitates communication with users such as CD equipment, using this pro~ocol.
The remaining subclaims relate to further advantageous embodiments of the invention.
The invention is not only suitable for application in automobiles but also in particular in aerospace vehicles due to the low weight ~-of the data transfer circuitry. In addition, networking stationary video, audio, telephone and data processing systems is also possible 2 0 8 ~ 9 5 9 by means of the bus system according to the invention to reduce the volume of the circuit connections formerly neceC~sary.
Further features and advantages of the invention result ~rom the following description of several embodiments ancl with reference to the drawing in which~
ig. 1 is a schematic diagram showing a system of users employing the method of the invention, ig. 2 serves to explain the data transfer formats used in the method r .,, ~.. :.
Fig. 3 illustrates the multiplexing step of the method, Fig. 4 shows a data sequence in a control data channel, ig. 5 is a schematic diagram showing how one of the interfaces is equipped for selecting the various audio sources, and Fig. 6 serves to explain the configuration and function of an ~ -interface between fiber optic cable sections and a system user.
In the embodiment shown in Fig. 1 an audio source 2, such as a radio receiver, for example, presents its audio signal to an input circuit 4 of an interface 6. The input circuit 4 for instance, can be one of the known circuits 12S, Sony bus or MSB-LSB-First having a variable format length. The audio source 2 is further connected to a control unit 8 which outputs certain control signals, for example, control ~
signals which determine which of several loudspeakers is to be ~ ;
signalled. These control signals are applied to interface 6 via a , ,' ~' ~` ' '.' . ~ ;-,"`` -~
~
:
-20859~9 suitable parallel or serial interface 10 of the latter where they ~ ;
are converted together with the audio data into a common serial data format which is described in more detail below and features a data channel for the control signals. Should no such control signals be available at interface 6, due to the radio receiver ~ailing to have such options, for example, the bits representing the control signals -~
are set to zero. The data clock is determined by the clock of the audio data stemming from the audio source 2, when it sends the data -in a suitable data format or by means 12 comprising a clock source and data buffer belongin~ to the interface. The data clock frequency is 32.0, 44.1 or 48.0 kHz, for example, corresponding to a baud rate of 2.0, 2.8 and 3.0 Mbaud respectively.
The seguence of audio and control data in common is converted by an -~
electrooptical converter 14 into a synchronous light signal which is applied to a fiber optic cable section LWL A. This embodiment is intended for a relatively compact system so that low-cost plastic fiber optic cables and converters of the simplest kind can be used.
Fiber optic cables of plastic can also be circuited with very small - -radii of curvature which is of a great advantage in an autombile, for example. The fiber optic cable section LWL A ends in an optoelectrical converter 16 of a second interface 6a which has an ~ ~
identical configuration to that of the interface 6 and which ~ -connects an audio processor 2a. The latter may be, for e~ample, a multi-channel bass/treble control. The audio data is made available to the audio processor 2a via a suitable output circuit 18 where the data is modified, as required, and returned to the interface 6a. In this embodiment the audio processor 2a also features a control unit 8a which is able to ~eact to control data contained in the data sequence and output by a suitable interface lOa or which is able to --output control data itself. - -:
'` ',' : :~ ", 2 0 ~ ~ 9 5 9 ~
The same as in the first interface 6, here too ~he data, which may be modified where necessary, are then applied to a second fiber optic cable section LWL ~ for monodirectional entry into a third ~ -~
interface 6b, again having the same configuration as that of interface 6, by means of which the data activates an audio sink 2b such as, for instance, an amplifier/speaker combination via which the audio signals are to be reproduced acoustically. The audio sink ~ ~
2b comprises a control unit 8b for receiving data from the control ~ `
data channel.
All interfaces 6, 6a and 6b have an identical configuration to rationalize their production; however, it is not always the case that they are used in their entirety.
Another feasible arrangement would be that the control unit 8b belonging to the audio sink 2b has a control data output to prompt corrections of the bass/treble control, should, for instance a speaker failure occur. It is good practice not only in this case to connect the third interface 6b via a third fiber optic cable section LWL C to the first interface 6 as is indicated by the dashed line in Fig. 1. Such a ring arrangement of users is, in fact, a preferred embodiment of the invention and is described in more detail below.
Fig. 2 shows the smallest unit 20 of the data format preferably used in view of the intended maximum-possible compatibility in accordance with the AES-EBU protocol for audio transfer in the consumer range and professional studio range AES3-1985 ( ANSI S4.40-1985, Standards and Information Documents, Audio Engineering Society, Inc., New York 1985). This unit 20 is termed a subframe and contains 32 bits. A
first group 22 of 4 bits in the unit 20 serves to synchronize and distinguish between the left-hand and right-hand stereo channel. A
second group 24 of 8 bits following in time sequence is available for audio data which is, however, still hardly made use of -~-~ ,, ':
2 0 8 5 9 5 .~
currently. This is followed by a third group 26 of 16 bits for audio data which is already used. The termination o~ a subframe 20 is formed by a sequence of discrete bits 28, 30, 32 and 34 of which bit 30 is termed the user bit and can be utilized by the user arbitrarily without affecting audio transfer. A~ regards the significance of the bits 28, 32 and 34 reference is made to the cited AES-EBU protocol. Each stereo channel is assigned a subframe 20, two of which follow in sequence in each case to form a frame, 192 frames then forming what is termed a block.
The user bit 30 causes a serial data channel to be opened which is subdivided into any number of subchannels by a time multiplex procedure. Fig. 3 shows, for example, the divisioning into 10 subchannels. Each 1st, 11th, 21st etc bit of the data sequence contained in the data channel opened by the user bit 30 is assigned as a subchannel to a channel 1, each 2nd, 22nd, 32nd etc bit to a channel 2, and so on. Each user transmits on a channel. For a total baud rate of 2 Mbaud a control data baud rate of 64 kbaud results for a 32 bit long subframe 20. In a preferred embodiment 8 subchannels are provided for each of which a transfer capacity of 8 kbaud thus remains, such a capacity being sufficient to transfer even complex infonmation.
Fig. 4 shows a special data sequence in one of the 8 user channels of four blocks n, n+1, n+2 and n+3, each 48 bits long ~384 -subframes/8 subchannels~. Each block bgsins with a bit 40 set to logical 1 to mark the start of the data sequence. This is followed by a start bit 42, this being set to logical 1 on commencement of the data message to be transferred and to logical 0 when the data message is continued with the next block. The start bit is followed by a 7 bit long address 44, each user being assigned a specific f address. The address 44 is followed by a bit 46 which the -~
,,~,," ,........
2~859~9 receiver of a data sequence can change to acknowledge receipt or inform the sender whether a channel is again vacant or whether the message was rejected. Bit 46 is followed by a bit sequence 48 containing coded information as to the length oi~ the subsequent actual data sequence. This data is transferred ln groups 50, identified in Fig. 4 by Datal, Data2, etc.
Fig. 5 is a schematic diagram showing how two further audio sources Auxl and Aux2 are coupled to the bus system via an interface 6. The configuration of interface 6 corresponds to that of the interfaces 6, 6a and 6b shown in Fig. 1. The selectors 52 and 54 which may also be implemented electronically permit the choice of signal feed from the audio sources Auxl and Aux2. In the special case in which the selectors 52 and 54 are both in the UP position in Fig. 5 the audio signals of the bus system pass the interface 6 unchanged.
The salient parts of one of the interfaces 6, 6a or 6b shown in Fig.
1 are depicted in the block diagram of Fig. 6. Parts which have already been explained in conjunction with Fig. 1 have received the same reference numerals. All parts with the exception of the electrooptical convertors 14 and 16 are implemented in a single ;
integrated circuit to save costs. The converters 14 and 16 are here considered as elements of the interface, but ln actual implementation can be connected right from the start with the fiber optic cables and are not connected electrically to the remaining -~
parts of the interface until the system is installed. A circuit 60 contains a phase locked loop PLL which tunes itself to the electrical signals coming from the one converter 16. Circuit 60 is also capable of determining when an address contained in the signals ;
agrees with an address assigned to the corresponding interface. In addition, the data sequence is applied to the receiver buffer 62.
The audio data is converted via an output circuit 18 into various ..... - . ~
-.`'.`'`'`'`'`'`,`".-2 ~ ~ 5 9 ~ 9 formats of which the one matching a respective connected audio unitis transferred. Control data is applied to a microprocessor of the connected user and back again via an interface 10 also designed to handle several formats. The control data to be t:ransmitted is applied via a transmit buffer 64 tO a multiplexing means 66, the `~
mentioned format being configured, on the one hcmd, and, on the other, the control data being read into the multiple~ channel correct in time. Audio data arri~ing from the connected audio unit via an input circuit 4, or, audio data from the receiver buffer 62 are also incorporated in the format and the complete data sequence is applied to a converter 14 which converts the electrical signals back into optical signals. Data management is the job of a control and status register 68 connected to the receiver buffer 62, the transmit buffer 64 and the interface 10. When an address contained in the data fails to agree with the user address the data is passed on unchanged. Due to buffering a certain shift in time results, this being arranged, however, so that the data is resorted into its correct channel. The clock information is received by the transmit buffer 64 from a clock circuit 70 which receives the clock either ~ -~
from the PLL circuit 60 or from a separate clock generator. This clock generator need not be a component of the interface, however, since commercially available audio sources such as CD players generally contain such a clock generator, this being the reason why it is not indicated.
As evident from Fig. 1 a basic distinction is made among three different modes of opPration as regards audio transfer. The mode of the interface 6 shown on the left in the Fig. is an active mode in ~;-which the mentioned data format is originally generated, i.e. based ~-either on the clock of the data stemminq from the audio source 2 or -~ -on the clock of a separate clock generator. In this so-called master mode only one interface of a system is ~ ~
.: ,~ '~`''.-.''.''.' - . , - .: - .
~ ~ .
--ll--208~959 operative at any one time. The two other interfaces 6a and 6b generate no clock of their own, but adapt by the!ir PLL circuit to the clock as specified. This mode of operation is termed slave mode.
Interface 6a shown in the middle of the Fig. ha a special feature, it being able to receive and also modify audio data when required.
In this case the mode i5 termed a slave/processor mode. The interface 6b on the right of the Fig. behaves purely passive as regards the audio data by it merely passing the data on.
An essential feature of the invention is that data transfer via the fiber optic cables is in one direction only. Only one user operates in the master mode and thus dictates the cl w k. Together with the fact that each user employs its own transmit channel and a bus arbitration is not necessary it is possible to connect a large number of users to a single network without transfer conflict -~
despite a high data thruput. Transmitting is possible on all control data channels at the same time, this being the reason why each control data channel has a mean data transfer rate which is available at all times. Compared to conventional bus systems of comparable performance the costs of realizing the system are exceptionally low. Nhen the first and last user are reconnected together a closed ring results in which a message can circulate until its receiver accepts it. The sender of a message is able to ;~
determine whether its message has arrived at the receiver. To this end, bit 46 is used which as already mentioned in conjun~tion with Fig. 4 is altered or removed by the receiver of a message to -~
acknowledge the receipt. -~
In one particular embodiment of the invention the audio data is rerouted already within the interface and directly retransmitted, namely when the connected user features no audio unit at all or merely executes control or monitoring functions.For instance, - ~ , ' `. '''`~ " ~.'~' , ' `- ~ ~' `' ' '`'`' '`'~;~,'` ` ' ` ' `' -, . ~-.
-12~
2085~59 the system can be used with any of the many types of sensors employed in a vehicle. In one embodiment of the invention these sensors can be interrogated within the scope of a vehicle diagnosis for which a separate diagnosis subchannel is prc~vided by means of a :~
transparent bit which is not manipulated and passes through the ~-chain of users without being changed.
~' :, , :'"' . .
: - . .::
.. . .
.-. ~ , ~ .
~ ~ .
': ;''' '~' ~
: .:
:'~, ~.. :..-` '' '~''''.''.''-'',''' : ~ ~ . ~ .. .. ,:
~. ~''".',.~
:- : - .
:: ;: .: :-`'':`' : ' ".;:~
-'~;`,`'; '.
'.~' :,, -.
: : -: .:
,. . ~ : .
Claims (18)
1. A method of common transfer of digital audio and control data on a common bus line in a user system to which at least one digital audio source and at least one digital control data signal source belong;
characterized in that:
said bus line is configured as a series circuit of fiber optic cable sections and interfaces, each of which connects two fiber optic cable sections by converting the signals arriving from a fiber optic cable section into electrical signals and feeding these into the other fiber optic cable section unchanged or converted into optical signals when processed;
the audio and control data is transferred in a format specifying a clocked sequence of discrete groups of bits of equal magnitude in which the audio data requires a predetermined number of bits in each case and at least one bit is reserved for the control data;
by means of time multiplexing several control data channels are formed on the bus line by means of the reserved bit of the bit groups;
each user employs an assigned control data channel for transmitting control data;
each user is connected to the bus line via an assigned interface;
an address is assigned to at least some of the users; and each user having an assigned address continuously interrogates the control data channels via its interface to respond to transferred control data when the address in advance of said control data agrees with the user address.
characterized in that:
said bus line is configured as a series circuit of fiber optic cable sections and interfaces, each of which connects two fiber optic cable sections by converting the signals arriving from a fiber optic cable section into electrical signals and feeding these into the other fiber optic cable section unchanged or converted into optical signals when processed;
the audio and control data is transferred in a format specifying a clocked sequence of discrete groups of bits of equal magnitude in which the audio data requires a predetermined number of bits in each case and at least one bit is reserved for the control data;
by means of time multiplexing several control data channels are formed on the bus line by means of the reserved bit of the bit groups;
each user employs an assigned control data channel for transmitting control data;
each user is connected to the bus line via an assigned interface;
an address is assigned to at least some of the users; and each user having an assigned address continuously interrogates the control data channels via its interface to respond to transferred control data when the address in advance of said control data agrees with the user address.
2. A method according to claim 1, wherein data transfer from one interface to the next is by means of a fiber optic cable section and monodirectional in each case.
3. A method according to claim 1 or 2, wherein the users are circuited together by a bus line in a closed ring system, each user modifies or removes a certain bit in the sequence of control data every time this user receives control data addressed to it and wherein the user outputting the control data monitors the control data returned to it via the closed bus line for changes therein.
4. A method according to any of the previous claims, wherein a coded information as to its length is also transmitted in each sequence of control data.
5. A method according to any of the previous claims, wherein the transfer format corresponds to standard AES3-1985 (AMSI S4.40-1985) requiring each bit group to comprise 32 bits of which 24 bits are employed for the audio data, 1 bit for forming the control data channels and the remaining bits for the checking and sync functions.
6. A method according to any of the previous claims, wherein one of the users operates in a master mode as the source of audio data while all other users operate in a slave mode as potential receivers.
7. A method according to claim 6, wherein said users operating in the slave mode by means of a phase-locked loop derive their clock from the clock of the user operating in master mode.
8. A method according to claim 6 or 7, wherein at least one of said users operating in the slave mode subjects the received audio data to processing as required.
9. A bus system for implementing the method according to any of the previous claims characterized in that each user is assigned a standardized interface of the same kind, each interface has an input and an output for connecting one end of each fiber optic cable, the interfaces are circuited in series by connecting one output of each interface to one input of another interface and each interface is provided with between its input and its output with means for converting optical signals into electrical signals, means for buffering received data and means for converting electrical signals into optical signals.
10. A bus system according to claim 9, wherein said series circuit of interfaces is closed to form a ring.
11. A bus system according to claim 9, wherein its use in a network involves at least two of the following users:
radio receivers, cassette recorders, CD players, amplifier/speaker combinations, sound processors, telephone components, measurement value sensors, actuators for implementing commands transferred via the fiber optic cable sections, means for data acquisition, data storage, data processing and data analysis, particularly in a vehicle.
radio receivers, cassette recorders, CD players, amplifier/speaker combinations, sound processors, telephone components, measurement value sensors, actuators for implementing commands transferred via the fiber optic cable sections, means for data acquisition, data storage, data processing and data analysis, particularly in a vehicle.
12. A bus system according to any of the previous claims, wherein said fiber optic cable sections are formed by plastic fiber optic cables.
13. An interface for employment in the method according to any of the claims 1 thru 8 and in the bus system according to any of the claims 9 thru 12 characterized in it containing:
an input connectable to a fiber optic cable section with an optoelectrical converter for converting optical signals into electrical signals, an output connectable to a fiber optic cable section with an electrooptical converter for converting electrical signals into optical signals, an input circuit for audio signals output from a user, an output circuit for audio signals to be output to a user, an input/output circuit for control data from and to a user and a means for buffering electrical signals.
an input connectable to a fiber optic cable section with an optoelectrical converter for converting optical signals into electrical signals, an output connectable to a fiber optic cable section with an electrooptical converter for converting electrical signals into optical signals, an input circuit for audio signals output from a user, an output circuit for audio signals to be output to a user, an input/output circuit for control data from and to a user and a means for buffering electrical signals.
14. An interface according to claim 8, wherein it contains a clock generator for producing the data format used in the method.
15. An interface according to claim 14, wherein the clock generator, depending on the operating mode of the user connected to the interface - master or slave - generates the clock automatically or derives it by means of a phase-locked loop from the signals arriving from a user operating in the master mode.
16. An interface according to any of the claims 13 thru 15, wherein it can be selected to operate in at least the following modes:
a) Master mode in which audio data from a user connected to said interface is fed to the fiber optic cable section connected to its output;
b) Slave mode in which the audio data arriving from a fiber optic cable section can be passed on unmodified to the other fiber optic cable section and, where required, to the user connected to said interface;
c) Slave/processor mode in which the audio data arriving from a fiber optic cable section can be modified by the user and fed to the other fiber optic cable section shifted in time, where necessary, but in synchronism with the data sequence.
a) Master mode in which audio data from a user connected to said interface is fed to the fiber optic cable section connected to its output;
b) Slave mode in which the audio data arriving from a fiber optic cable section can be passed on unmodified to the other fiber optic cable section and, where required, to the user connected to said interface;
c) Slave/processor mode in which the audio data arriving from a fiber optic cable section can be modified by the user and fed to the other fiber optic cable section shifted in time, where necessary, but in synchronism with the data sequence.
17. An interface according to any of the claims 13 thru 16, wherein it features several inputs for users operating as audio sources and switching means for selecting among the inputs.
18. An interface according to any of the claims 13 thru 18, wherein the input/output circuits can process differing standards for the control data from and to a user.
Priority Applications (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP91110247A EP0519111B1 (en) | 1991-06-21 | 1991-06-21 | Method and system for transmission of digital audio and control data on a common bus, and interface used for the system |
| JP4510742A JPH06500454A (en) | 1991-06-21 | 1992-06-15 | A method for transmitting digital audio and digital control data together over a common bus line, a system for realizing this method and an interface for implementing this method |
| PCT/EP1992/001351 WO1993000752A1 (en) | 1991-06-21 | 1992-06-15 | Process for the joint transmission of digital audio and control data on a shared bus line, bus system for implementing the process and interface for use with the process |
| PT100598A PT100598A (en) | 1991-06-21 | 1992-06-17 | PROCESS FOR THE COMMON TRANSMISSION OF DIGITAL AUDIO DATA AND COMMAND DATA THROUGH A COMMON OMNIBUS LINE, SYSTEM OF OMNIBUS LINES FOR THE REALIZATION OF THE PROCESS AND INTERFACE TO BE USED IN THE PROCESS |
| NL9201071A NL9201071A (en) | 1991-06-21 | 1992-06-18 | METHOD FOR COMMON TRANSFER OF DIGITAL AUDIO AND CONTROL DATA ON A COMMON BUS PIPE, BUS SYSTEM FOR CARRYING OUT THE METHOD AND CONNECTING DEVICE FOR USE IN THE METHOD |
| ITTO920527A IT1259584B (en) | 1991-06-21 | 1992-06-19 | PROCEDURE FOR THE COMMON TRANSMISSION OF DIGITAL COMMAND AND AUDIO DATA ON A COMMON BUS CONNECTION, BUS SYSTEM FOR THE EXECUTION OF THE PROCEDURE AND INTERFACE TO BE USED FOR THE PROCEDURE |
| CA002085959A CA2085959A1 (en) | 1991-06-21 | 1992-12-21 | Method of common transfer of digital, audio and control data on a common bus line; bus system for implementing the method and interface for application in the method |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP91110247A EP0519111B1 (en) | 1991-06-21 | 1991-06-21 | Method and system for transmission of digital audio and control data on a common bus, and interface used for the system |
| CA002085959A CA2085959A1 (en) | 1991-06-21 | 1992-12-21 | Method of common transfer of digital, audio and control data on a common bus line; bus system for implementing the method and interface for application in the method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2085959A1 true CA2085959A1 (en) | 1994-06-22 |
Family
ID=25675767
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002085959A Abandoned CA2085959A1 (en) | 1991-06-21 | 1992-12-21 | Method of common transfer of digital, audio and control data on a common bus line; bus system for implementing the method and interface for application in the method |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0519111B1 (en) |
| JP (1) | JPH06500454A (en) |
| CA (1) | CA2085959A1 (en) |
| IT (1) | IT1259584B (en) |
| NL (1) | NL9201071A (en) |
| PT (1) | PT100598A (en) |
| WO (1) | WO1993000752A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5923662A (en) * | 1995-06-12 | 1999-07-13 | Stirling; Andrew J. | Communication system message acknowledgement |
| US6584099B1 (en) | 1993-12-10 | 2003-06-24 | Sony Corporation | Communication command system and method |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4222321A1 (en) * | 1992-07-08 | 1994-01-13 | Duerrwaechter E Dr Doduco | Method and circuit arrangement for supplying loudspeakers and other electrical consumers in vehicle doors with signals |
| GB9226580D0 (en) * | 1992-12-21 | 1993-02-17 | D2B Systems Co Ltd | Local communications system with plural data channels |
| DE4301816A1 (en) * | 1993-01-23 | 1994-07-28 | Sel Alcatel Ag | Telecommunication device in motor vehicles |
| DE4418337A1 (en) * | 1994-05-26 | 1995-11-30 | Mb Quart Akustik Und Elektroni | Method and device for reproducing sound signals as well as control device and sound reproduction device |
| DE19503215C1 (en) * | 1995-02-02 | 1996-10-02 | Becker Gmbh | Method for the joint transmission of digital source and control data between data sources and sinks connected via data lines |
| DE19503213C2 (en) * | 1995-02-02 | 1996-10-17 | Becker Gmbh | Method for the joint transmission of digital source and control data between data sources and sinks connected via data lines |
| DE19503212C1 (en) * | 1995-02-02 | 1996-10-02 | Becker Gmbh | Process for the transmission of digital data |
| DE19503207C2 (en) * | 1995-02-02 | 1996-09-19 | Becker Gmbh | Method for the joint transmission of digital source and control data between data sources and sinks connected via data lines |
| DE19503214C1 (en) * | 1995-02-02 | 1996-10-02 | Becker Gmbh | Procedure for initializing a network |
| DE19503206C1 (en) * | 1995-02-02 | 1996-08-14 | Becker Gmbh | Method for determining the position of a network subscriber in a network in the event of a line fault |
| DE19503210C1 (en) * | 1995-02-02 | 1996-09-12 | Becker Gmbh | Process for the transmission of digital data |
| JP3454653B2 (en) * | 1996-12-27 | 2003-10-06 | 矢崎総業株式会社 | Data transmitting device, data receiving device, data communication device, and data communication method |
| EP0960509B1 (en) | 1997-02-17 | 2005-12-07 | COMMUNICATION & CONTROL ELECTRONICS LIMITED | Local communication system |
| DE19723989C1 (en) * | 1997-06-06 | 1998-12-10 | Becker Gmbh | Television receiver system for automotive applications |
| DE19735545C1 (en) * | 1997-08-16 | 1998-12-17 | Grundig Ag | CD-Audio sound system for motor vehicle |
| DE19757195A1 (en) * | 1997-12-22 | 1999-06-24 | Philips Patentverwaltung | Method for transmitting an asynchronous data stream over a synchronous data bus, and circuit arrangement for carrying out the method |
| DE19921626C2 (en) * | 1999-05-10 | 2003-04-03 | Harman Becker Automotive Sys | Local network and method for reproducing audio and video data in such a network |
| DE10260415A1 (en) * | 2002-12-21 | 2004-07-01 | Volkswagen Ag | Preparing and storing technical data and parameters in motor vehicle involves storing in unified database or in unified data format in enabling export/import as compact data packet |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0176788B1 (en) * | 1984-09-05 | 1989-12-13 | Hitachi, Ltd. | Multiplex communication system |
| JPS61264835A (en) * | 1985-05-17 | 1986-11-22 | Kawamura Denki Sangyo Kk | Optical fiber data link system |
| DE3928239A1 (en) * | 1989-08-26 | 1991-02-28 | Thomson Brandt Gmbh | Data transmission system for remote control - has central control point with interface distributing remote control signals to controlled electronic devices |
-
1991
- 1991-06-21 EP EP91110247A patent/EP0519111B1/en not_active Expired - Lifetime
-
1992
- 1992-06-15 WO PCT/EP1992/001351 patent/WO1993000752A1/en unknown
- 1992-06-15 JP JP4510742A patent/JPH06500454A/en active Pending
- 1992-06-17 PT PT100598A patent/PT100598A/en not_active Application Discontinuation
- 1992-06-18 NL NL9201071A patent/NL9201071A/en not_active Application Discontinuation
- 1992-06-19 IT ITTO920527A patent/IT1259584B/en active IP Right Grant
- 1992-12-21 CA CA002085959A patent/CA2085959A1/en not_active Abandoned
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6584099B1 (en) | 1993-12-10 | 2003-06-24 | Sony Corporation | Communication command system and method |
| US7151771B2 (en) | 1993-12-10 | 2006-12-19 | Sony Corporation | Communications system |
| US7190694B2 (en) | 1993-12-10 | 2007-03-13 | Sony Corporation | Communications system |
| US5923662A (en) * | 1995-06-12 | 1999-07-13 | Stirling; Andrew J. | Communication system message acknowledgement |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0519111A1 (en) | 1992-12-23 |
| NL9201071A (en) | 1993-01-18 |
| PT100598A (en) | 1994-05-31 |
| JPH06500454A (en) | 1994-01-13 |
| EP0519111B1 (en) | 1997-05-02 |
| IT1259584B (en) | 1996-03-20 |
| ITTO920527A1 (en) | 1993-12-19 |
| WO1993000752A1 (en) | 1993-01-07 |
| ITTO920527A0 (en) | 1992-06-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |