JPH0267837A - Wire communication method - Google Patents

Abstract

PURPOSE:To keep complete information secrecy by subjecting data, which is ciphered with a prescribed cipher code string, to spectrum spread, what is called, double ciphering. CONSTITUTION:The transmission part of each of communication equipments 1-i and 1-j subjects data inputted to a balanced modulator 12 to spectrum spread modulation by a prescribed PN code string generated by a PN code (pseudo random noise code) string generator 11 and modulates a carrier fc in a modulator 14 by its waveform signal. The signal subjected to spectrum spread modulation is superposed on a wire signal transmission line (power line or the like) 2 through a coupling device 20. Meanwhile, the reception side receives ciphered data subjected to spectrum spread modulation through the coupling device 20 coupled to the wire signal transmission line 2 and subjects this data to spectrum spread demodulation and uses a cipher code string to decode ciphered data and reads it as reception data. Thus, secrecy of transmission information is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wired communication method, and in particular, to improving the confidentiality and communication reliability of data when transmitting and receiving data between at least two or more communication devices. , to clearly distinguish a specific group from other groups, to enable communication only within a specific group, and even within a specific group, only to a specific combination of communication devices. This invention relates to improvements to enable communications that maintain confidentiality.

[Prior Art] Many communication device systems that attempt to exchange data using wired signal transmission lines have been proposed for a long time, and in fact,
Various types of systems have been put into practical use, but recently there has been a strong demand for this type of system to be able to maintain the confidentiality of transmitted information.

For example, only between a fixed set of communication devices,
Furthermore, if signals are sent and received using a dedicated wired signal transmission line, and if the system configuration is such that not everyone can easily access the wired signal transmission line, then Regarding information transmission, no special consideration is given, and simple AM modulation or FM modulation is sufficient.

However, in reality, if a malicious third party attempts to intercept information, for example, there is a risk of installing an appropriate coupling device on the installed wired signal transmission line to extract the signal, no matter how dedicated the wiring is. cannot be completely eliminated,
In fact, recently there has been a demand for system hardware to be as simple and rational as possible, so there have been proposals to use existing power wiring in buildings as wired signal transmission lines for this type of use. These power lines are usually equipped with several outlets to connect various electrical devices, so if you feel like it, you can easily access the power wiring as a signal transmission line through these outlets. It is easy to intercept and eavesdrop on the information superimposed on it.

Furthermore, even if it is not done maliciously, if there are multiple offices in one building or building, and all of these offices use the shared power wiring to communicate information, It is very possible that data at one office could be intercepted by communication equipment at another office, which is generally disadvantageous.

In fact, in such a communication system that uses power wiring,
In order to connect the communication equipment used for this to the power wiring without special construction, simply plug the power plug of the communication equipment into the normal outlet attached to the power wiring, and the transmitted data will be superimposed on the power line. A coupling device is even connected to the power line, so if you consider these things together, you will find that the situation is disadvantageous for preventing wiretapping, regardless of whether or not there is malicious intent.

However, it is true that the system that uses the power line green system inside the building to transmit information as described above does not require dedicated lines for information transmission and does not require large-scale construction. Since it can be constructed, it is not only inexpensive, but also has the fundamental advantage that it does not damage the appearance of the interior or exterior of the building, making it quite attractive in its own way.

Therefore, conventionally, an information modulation method has been developed that maintains the simplicity of system construction, maintains the confidentiality of transmitted information, and does not adversely affect ordinary electrical and electronic equipment connected to power wiring. , spread spectrum (S
S: Spectrum 5pread) modulation method was proposed.

The present applicant also developed a system for monitoring and controlling air-conditioning cooling towers installed in remote locations, such as on rooftops, from a central control room located in a room (basement, etc.) within a building. An example of this is disclosed in No. 196546, and as filed separately from the present application, information on vending machines etc. installed in various places in a building is obtained using a terminal communication device, and this information is collected. He proposed that it would be desirable to use such a spread spectrum modulation method when using power wiring within buildings in systems that send data to stations.

However, the principle of the spread spectrum method as a signal data modulation/demodulation method is old and already well known, and there are various specific modulation methods for specific purposes, such as direct sequence (DS) modulation, frequency hopping (FH) ) modulation, pulsed frequency modulation (Pulsed FM) or Chilb modulation (CM), etc. However, since numerically it is direct spread modulation, just to be sure, the relevant spread spectrum when following this modulation An example of the configuration of the modulation/demodulation circuit is shown in FIG. 5 and explained below.

For simplicity, only two communication devices 1 and 1-J are shown in FIG. Modulation/demodulation circuit (SS-modem) 10. to are both configured in the same way.

Now, when trying to send data from the communication device 1-1 to the communication device 1j, the transmission data is sent to this communication device 1-1.
The balanced modulation is applied to the balanced modulator 12 as a primary modulator provided in the SS-modem 10 of multiplied and spread spectrum.

This spread-spectrum transmission data is further modulated by a carrier wave fc given from a carrier wave oscillator 13 in a secondary modulator 14, and is sent to a wired signal such as a power line via a coupling device 20 having an appropriate filter capacitor or coupling transformer. Superimposed on transmission line 2.

As a result, the signal transmission line 2 has communication devices 1. The transmitted data from the transmitter is preferably superimposed as a spread spectrum signal by carrier suppression.

The spread spectrum modulated data is transferred to the signal transmission line 2.
is transmitted to the modulator 1 via the same coupling device 20 provided in the SS-modem IO of the communication device 1-J.
The signal is inputted to a modulator 15 having substantially the same configuration as 4, where it is mixed with a carrier wave fc from a carrier wave oscillator 13, frequency converted, and then sent to a balanced modulator 16 constituting a spread spectrum demodulator. Correlation is detected using the same PN code string used for transmission, and the data is demodulated as received data. Therefore, the modulator 15 functions as a so-called mixer in a receiving system, and the balanced modulator 16 functions as a correlation detector for spread spectrum signals.

Such functions are available from the communication device 1J to the communication device! -1 occurs in exactly the same way, but communication device 1
．． In the SS-modem 10 of the communication device 1, a balanced modulator 12 and a modulator 14 involved in transmission are connected to the SS-modem IO of the communication device 1.
In this case, only the modulator (mixer) 15 and balance modulator (correlation detector) 16 involved in reception are changed as much as possible.

Instead of such a direct sequence modulation/demodulation method, even if the direct sequence modulation/demodulation method is basically the same, instead of spreading the data spectrum and then modulating the carrier wave fc as shown in Figure 5, the carrier wave is pre-modulated using a PN code. There is also a method that modulates the data after spreading the spectrum.
In any case, in addition to this direct sequence method, other frequency hopping (FH) modulation and pulsed frequency modulation (P
When using this type of spread spectrum modulation method, the voltage peak value of each frequency value within a widely spread transmission frequency range becomes small, and in some cases becomes lower than the noise level. However, since the total amount of energy within the wide spread frequency band can be large, it is resistant to interference, and there is little risk of it becoming a source of interference waves, and it is Since demodulation cannot be performed without knowing the random noise pattern, it can also be used as a type of encrypted communication to some extent.

In other words, with this spread spectrum method, the power density per unit frequency does not increase the transmission output power to an unreasonable extent, and even if the existing power wiring system in the building is used as a signal transmission line, it is possible to It is possible to suppress the voltage level to a sufficiently low level so as not to affect the various loads IO normally connected to the IO, and still obtain a sufficient S/N ratio, and, in principle, to maintain a considerable degree of communication. This has the advantage of providing confidentiality. In the applicant's demonstration, it has been confirmed that there is almost no adverse effect on computers and other digital devices that are susceptible to noise interference, and that the transmission line impedance is abnormal at specific frequency values within the spread frequency band. Even if only that frequency component is significantly lowered or damaged due to a significant drop,
It was also recognized that interpolation is effective for other frequency components and that signal reproducibility is excellent.

However, in this spread spectrum method, for demodulation it is necessary to calculate the correlation coefficient with the same PN code pattern used during modulation, and this is actually a convolution operation, which requires high speed and large It required a high-capacity digital circuit, which delayed its widespread use. Recently, not only has it become possible to provide integrated circuits for such convolution integral calculations, but also a surface acoustic wave device called a SAW converter has advanced to the point where analog calculations can be performed in two-dimensional space. The fact that convolution integral calculations can now be easily performed with a single element has spurred the practical application of spread spectrum methods.

[Problems to be Solved by the Invention] As mentioned above, the spread spectrum method is used as a signal modulation/demodulation method, so that the effect is particularly noticeable when using an existing power wiring system in a building as a wired signal transmission line. If adopted, it seemed that there was a chance for practical use in terms of noise and interference countermeasures. In addition, if the communication groups are the same group and there is no need to maintain any secrecy between them, such spread spectrum modulation and demodulation alone can protect the communication to a certain extent from third parties outside the group. It was also found that the confidentiality of the information can be guaranteed.

However, as a practical problem, for example, as mentioned above, one building or multiple offices are housed within a building, and among these offices, only the subscribers are using the power wiring within the building. For example, in cases where communication between multiple floors is permitted, it is not only possible to communicate between floors of the same office occupying multiple floors, but also between different offices occupying multiple floors within the same building. , it would be bad if the contents of the communication were received, and such a communication system would be difficult to accept in reality.

In other words, considering the subscribers as one group in the above,
If a combination of specific members within the subscriber group is defined as a sub-group, it is natural to guarantee that the members within the group can freely use the constructed wired signal transmission system. It is also conceivable that communications between members of a sub-group must be kept confidential in the same way as with third parties outside the group.

As will be shown later in the embodiments of the present invention, an information management company that obtains individual information from each communication device in a building using the public telephone network can also send information to other users in the same way. This problem can also occur when manually digging out the information using the public telephone network. Users who have a contract with an information management company constitute one group.
Although users can always participate in the system, each user may form an independent sub-group with respect to other users, and it may be necessary to prevent information about other sub-groups from being accessed manually. It is.

In such a case, as a mere theoretical theory, since the spread spectrum method is adopted as the signal modulation/demodulation method, if the combination of PN code strings applied to each sub-group is changed, This can also reduce the possibility of erroneous reception between different sub-groups.

However, when constructing such a communication equipment system, the operator of the system is often an independent operating company, and in such cases, the communication equipment owned by the operator is used as a kind of mask-like communication equipment. It is necessary to be able to communicate with all communication devices owned by the subscriber, including the data contents, when necessary.

Therefore, in order to satisfy this requirement, the modulation/demodulation part involved in spread spectrum must be configured in the mask communication device so that it can be applied to all communication devices.

However, this puts a heavy burden on the circuitry of the communication equipment owned by the operating company, and also requires that each subscriber's communication equipment be able to link to the communication system regardless of the PN code string assigned to it. In addition, all possible combinations of PN code strings must be configured to realize this. Nevertheless, this is a bit wasteful considering that in actual use only one combination needs to be used.

In particular, as mentioned earlier, the part involved in spread spectrum modulation and demodulation, that is, the SS-modem 1 in Figure 5.
The 0 part tends to be expensive even if it is not. Therefore, I would like to keep the circuit configuration of this part as simple as possible.

Nowadays, parts called SS-modems corresponding to the modulation/demodulation circuit 1O shown in Fig. 5 are sometimes commercially available. We want to keep the data capacity related to spread spectrum to a small level.

On the other hand, some SS-modems that are provided use, for example, M-sequence codes that are generated using shift registers as PN codes, but such models are not designed for circuit miniaturization or low cost. In order to maintain high performance, the number of stages of shift registers may not be so large.

Therefore, even if a spread spectrum method is used, if a malicious third party attempts to intercept information, this cannot be completely prevented. If the number of stages of a commercially available shift register is known and the number is not too large, obtaining a possible PN code string is not that difficult using recent analysis techniques.

In view of these circumstances, the present invention has been devised to reduce the burden on the circuit system involved in spread spectrum, with regard to information transmission using a wired signal transmission line, without sacrificing any of the advantages of the spread spectrum method. In addition to ensuring high confidentiality of the transmitted information, it also provides flexibility when distinguishing between groups and outside groups, and enabling communication only between the same subgroups even within the same group. The aim is to propose an advanced communication method.

[Means for Solving the Problems] In order to achieve the above object, the present invention basically modulates transmission data with a cryptographic code string on the transmitting side, and then further spread spectrum modulates the encrypted data. ,
This spread spectrum modulation data is superimposed on the wired signal transmission line via a suitable coupling device.

In response, the receiving side receives the encrypted data that has been subjected to spread spectrum modulation via a coupling device coupled to the wired signal transmission line, obtains the encrypted data by performing spread spectrum demodulation, and then , the encrypted data is decoded using the same cryptographic code string as used during transmission, and read as received data.

Of course, each communication device may be provided with a pair of the above-described configurations on the transmitting side and the receiving side, thereby enabling time-division bidirectional communication between such communication devices.

Furthermore, if there are at least two communication devices having the above basic configuration and they are connected to each other via a wired signal transmission line installed in one building,
A configuration is also proposed in which at least one of the at least two or more communication devices is communicably connected to another external communication device via a public telephone network.

In such a case, the communication device in the building connected to the external communication device transmits the encrypted spread spectrum modulated data to the external communication via the public telephone line while transmitting the spread spectrum modulated encrypted data in the spread spectrum modulated state. We also propose a configuration in which the encrypted data is sent to the external communication device via the public telephone network, with spread spectrum demodulation first performed, but without decryption, as encrypted data.

Of course, when communicating from an external communication device to the above-mentioned communication device installed in the building via the public telephone line, the data must be encrypted before being sent, or even spread spectrum must be applied. You can choose to send.

In any of the above cases, as the wired signal transmission line, a power line installed in a building and installed inside the building can be used.

[Operations and Effects] According to the basic configuration of the present invention, information transmitted by wire is, so to speak, doubly encrypted. In other words, since data encrypted using a predetermined code string is spread spectrum, even if a third party obtains a PN code string that will be used for spread spectrum, it will not be possible to read the true data with just that. In fact, almost perfect information confidentiality can be maintained.

Additionally, as mentioned earlier, double encryption processing guarantees the use of the communication system within the group, but also makes it impossible for subgroups within the group to communicate with each other. It is also easy to carry out the process.

For example, when creating a situation where multiple subscribers forming a specific group are permitted to transmit wired signals only within the same building using the existing power wiring in that building,
A predetermined PN code string is taught to all subscribers belonging to those groups, and spread spectrum demodulation is always enabled in the communication equipment owned by each subscriber within the group. If each communication device is given a code string with a pattern different from the code strings set in the communication devices of other subscribers,
At least between different subscribers, the encrypted information is only demodulated and cannot be decoded to the true data, so mutual confidentiality of information can be sufficiently maintained.

In other words, the cryptographic code string used in the present invention is an identification code (ID) that specifies each subgroup within the group.
This means that it can also be used as a code (code), and also contributes to simplifying the organization of various system information attached to this type of communication system.

In summary, it is possible to distinguish whether a person belongs to a group or a communication device of that person by knowing the pattern of the adopted PN code string, and then whether or not the code strings are the same. Accordingly, it is possible to discriminate whether or not the communication devices belong to the same sub-group.

Therefore, if people outside the group do not know the patterns of both the PN code string and the code string used for spread spectrum, even if the wired signal transmission line itself is the existing power wiring in the building, etc. Even if the communication is relatively easily accessible, it is impossible to intercept the contents of the communication, and within a group that is permitted to use such power wiring to conduct wired communication at any time. Even if it is a person, the communication contents of other sub groups given different from the encryption column pattern given to themselves cannot be intercepted unless the code is deciphered.

However, of course, even if there are only communication devices belonging to one group in one building, the effectiveness of the present invention is not impaired in any way. The most basic effect of doubly maintaining the confidentiality of information from people outside the group can be maximized, and for example, if a company operating such a communication system When constructing a similar communication system, without making any changes to the SS-modem part involved in spread spectrum as each communication device, users who wish to join this system will be able to access it in any building and by anyone. In addition, in order to manage buildings in various fields, it is possible to provide communication devices with substantially the same configuration, and in addition, in order to manage buildings in various fields, a specific cryptographic code string is used as an ID code to identify each building. Setting a pattern simplifies the management of communication equipment for each building by the operating company.

To put the above in reverse order, even if a relatively inexpensive and simple circuit is used for the spread spectrum modulation/demodulation circuit (SS-modem), the present invention provides sufficient information security. This means that the quality can be guaranteed.

The present invention, which has such excellent effects, can be applied to systems that also utilize public telephone lines as wired signal transmission lines.

Therefore, it is possible to use both encryption and spread spectrum for data transmitted over the public telephone network, and if this is done, for exactly the same reasons as mentioned above,
The confidentiality of information is maximized, and the code can also be used as an identification code for each building or communication device.

Instead, only with respect to the transmission of information within a building, both encryption and spread spectrum are used, with at least one communication device located within the building and established in an area separate from the building. Even if only encryption codes are used for communication using public telephone lines with external communication equipment installed at information management companies, etc., multiple sub-groups may exist within the building. In addition to being able to distinguish between these cases, it is still possible to perform information transmission that maintains the confidentiality of one communication up to the final terminal receiving device installed by the information management company.

Furthermore, this system can be expanded to provide information obtained in advance using the public telephone line to multiple users with whom the information management company has a separate contract.

As described above, according to the present invention, in addition to enjoying the advantages of the spread spectrum method, from a more practical standpoint, even if the load on the circuitry required for spread spectrum modulation and demodulation is reduced, even higher information transmission can be achieved. The cipher code can be used as a type of ID code if necessary, so its application range is extremely wide.

In particular, when using existing power wiring in a building as a wired signal transmission line, which is attracting attention at the moment, such power wiring itself has the most inadequate anti-interception measures, so the present invention has the greatest effect. becomes.

Furthermore, the present invention can contribute to increasing the number of communication channels if necessary.

For example, even if a PN code is configured with a small number of bits, all encrypted code string patterns can be assigned to each PN code string pattern, so in principle, the total number of encrypted code strings obtained is The number of channels can be increased.

[Embodiment] FIG. 1 shows an example of the configuration of a data modulation/demodulation section of a communication device used in the communication method of the present invention.

However, for the purpose of understanding the present invention, this configuration is shown as an improved example of the conventional configuration shown in FIG.
0 indicates the communication device 1.0 shown in the fifth diagram. , l, is exactly the same.

In other words, this corresponds to the case where direct spread modulation (DS modulation method) is adopted as a detailed method of spread spectrum modulation. On the other hand, spread spectrum modulation is applied using a known PN code string generated by a PN code string generator ti, and the carrier wave fc is further modulated by a modulator 14 using the waveform signal.Carrier wave fc is obtained from the carrier wave finder 13 in which the oscillation frequency value is set in advance.

Each communication device 1. ．． The spread spectrum modulated signal output from the modulator 14 of 1 has an appropriate filter capacitor and coupling transformer (not shown in detail),
It is superimposed on a wired signal transmission line 2, such as an existing power line in a building, via a coupling device 20 that can be easily configured using known technology.

In particular, when the wired signal transmission line 2 is a power line as described above, the coupling device 20 cannot be plugged into a normal outlet, as seen in the conventional configuration of the section (not shown in FIG. 1). It has a plug that can be inserted into an outlet, and when it is inserted into an outlet, it is configured so that it can supply power to itself from the power line and output a spread spectrum modulated wave of encrypted data to the power line. desirable.

The spread spectrum modulated information signal on the wired signal transmission line 2 is transmitted to each communication device 1-. .

1, and can be captured by the modulator 15, which serves as a mixer with the carrier wave fc. In fact, the modulator 15 constituting this mixer can have substantially the same or similar configuration as the modulator 14 previously used for data transmission.

The output of the modulator 15 is input to a balanced modulator 16 as a correlation detector involved in spread spectrum demodulation, where P
Correlation detection is performed using a known PN code string obtained from the N code string generator 15 and having the same pattern as that used during transmission,
The balanced modulator 16 outputs the spread spectrum demodulated data.

Up to this point, the configuration can be similar to that of existing spread spectrum type communication equipment, and as already mentioned, the S
As for the S-modem IO configuration, as shown in the figure, the data to be transmitted is subjected to spread spectrum modulation, and then the carrier wave f
Instead of modulating the carrier wave fc, the carrier wave fc may be spread spectrum modulated using a PN code sequence, and data may be modulated using the direct spread modulation method. In addition, other methods such as frequency hopping may be used. It may be configured as an SS-modem IO appropriate for the pulsed frequency modulation method or pulsed frequency modulation method.

For this reason, except for this Figure 1, in Figures 3 and 4 used for later explanation, the SS-modem IO is simply shown surrounded by a frame, and specific examples of the internal circuit configuration are omitted. , it was implied that any SS method could be adopted.

The characteristic part of the present invention is that in the configuration shown in the first figure, the SS
- It can be seen that the data to be input to the modem 1O is already data obtained by predetermined encryption processing of the transmission data.

That is, the data to be transmitted is transmitted to the data encryption circuit 30.
The signal is inputted into an encryption modulator 32 inside, where it is modulated in advance by a code string generated by a separate encryption code string generator 31.

As a result, each communication device 1. ．． As a result of spread spectrum demodulation of the received signal at lj, the SS-modem 10
The data obtained at the output (in the illustrated configuration, the output of the balanced modulator 16) is also in the encrypted form as it is.

Therefore, communication device 1 using the present invention. ,l.

Then, the received output of the SS-modem IO is further input to the data decoding circuit 34, and the decoding modulator 33 built in the circuit 34 demodulates it using the same encrypted code string used for encryption (substantially The same modulation process as when transmitting is sufficient)
As a result, true transmission data sent by the transmitting side can be output from the data decoding circuit 34 as received data.

The present invention does not specify such encryption modulation or the corresponding decryption method itself. For this purpose, any known and existing encryption technology may be used as appropriate, but simply, if the data to be sent and received is binary data and the code string for encryption is also the same, ,
Appropriate encryption modulation can be performed by exclusive NORing or multiplication of these binary signal code strings using a simple gate configuration. Demodulation can of course be carried out with a corresponding gate configuration. Incidentally, regarding the spread spectrum modulation/demodulation circuits 12 and 16 as well, when performing spread spectrum modulation on data, multiplication of the data group by a PN code string or exclusive NOR logic is often used.

In any case, the communication apparatuses 1, 1, and 1 configured in accordance with the most basic form of the communication method of the present invention in this manner.
=1 has a configuration in which transmission data is encrypted by the encryption circuit 30 and then subjected to spread spectrum modulation, and received data is spread spectrum demodulated and then decoded by the decoding circuit 34.

Therefore, the true data information carried on the wired signal transmission line 2 requires knowing both the pattern of the adopted PN code string and the pattern of the encrypted code string generated by the encrypted code string generator 31. If this happens, it will never be demodulated, and extremely high information confidentiality can be maintained from third parties unrelated to the communication system using this communication device.

Note that in the case shown in the first diagram, which communication devices 1, . 1
- are both shown as communication devices capable of transmitting and receiving, but a combination in which one is configured exclusively for transmitting and the other exclusively for receiving is also conceivable, and in such a case, on the transmitting side, the carrier waves involved in reception can be A modulator 15 and a data decoding circuit 16 are used on the receiving side, and an encrypting circuit 1 involved in transmission
2 and the carrier wave modulator 14 are no longer necessary.

Of course, whether the communication is two-way or one-way, the encrypted code string is the same only between communication devices that form a pair or set for such communication, and for other pairs or sets. It is preferable that the values can be set and changed by operating the encrypted code string generator 31 so that the values are different.

However, many of the recent communication devices using the spread spectrum modulation method have a built-in microcomputer for communication control, etc., and in such cases, the code string generator 31 is operated by the microcomputer. This micro-
By changing the computer so that it generates the desired encrypted code string, the data encryption circuit 34 and the data decryption circuit 33 can be changed from what was shown as a separate hardware configuration in the diagram to the data encryption circuit 34 and the data decryption circuit 33, as the case may be. Both can also be conceptually replaced as circuits built into a microcomputer.

However, by using such a communication device according to the present invention, a communication system as illustrated in FIG. 2 can be constructed.

Here, as the wired signal transmission line 2, an existing power line within a specific building 60 is used.

Electric power company distribution lines are drawn into the building 60 in a known and usual manner, and the output of at least one transformer 62 is connected to a single-phase two-wire or single-phase three-wire output of commercial AC toov, or an AC 200v output can be obtained.

Normally, the output of the transformer 61 is distributed via a power distribution flI 62 to each distribution board 63 installed at least one on each floor.

The output of each power distribution [63] includes a power line and a wiring system for lighting equipment (not shown), as well as a power line having a plurality of outlets for supplying power to equipment using a normal commercial AC 100V power source. In this type of field, the lines to which these outlets are connected are also generally called power lines, so
This book also follows this.

In addition, the illustrated building shows the nth floor, where n is an integer greater than or equal to 1, and therefore, although the Heike is included, the basement is not shown, but this is just for explanation, and of course, the basement ml! The following explanation can be applied as is even to a building that has a hierarchical structure of @. Furthermore, the i floor in the figure represents any floor from the 1st floor to the nth floor.

A communication device 1 according to the present invention, one for each floor, is connected to the power line output from each distribution board 63.

That is, each communication device 1 in FIG. 2 may be the communication device '-+1-j shown in FIG. 1. However, −
The communication device 1 shown on the floor is also given another symbol IS, which indicates that this communication device IS can be used later as an information collection station or a relay station. This is to distinguish between the devices 1 and 1.

As mentioned earlier, each communication device 1 has a coupling device 2 that can supply power and superimpose and extract signal waveforms by simply inserting its own plug into the outlet attached to the power line.
It is good to have 0 (Figure 1), but in this way,
When each communication device l is communicably connected via a power line or a so-called main line between each distribution board and a switchboard, applying the present invention will first of all cause a third party unrelated to the communication system to In contrast, double secrecy processing is implemented, including encryption processing and a type of encryption processing using spectrum spread, resulting in a system with extremely high protection against signal leakage, eavesdropping, and interception.

For example, if all the communication devices 1 in FIG. 2 are configured to be able to transmit and receive without distinction, it goes without saying that
The time-series pattern of N code strings and the time-series pattern of the cipher code string used for encryption are the same for all communication devices 1...
・It is good to set it in common.

On the other hand, if you configure sub-groups for each of several communication devices 1 and only allow communication between these sub-groups and do not want other sub-groups to know the transmission information content, It is only necessary to set different encrypted code string patterns for each sub-group.

This is extremely convenient in a case where this type of communication system is managed by a corporate organization separate from each business office located within the building 60 and the use of such communication system is made available for a fee. Even if all the circuit parts involved in spread spectrum are the same and the patterns of the PN code strings used for modulation and demodulation of spread spectrum are set the same, simply changing the pattern of the encrypted code string can change the sub-code strings. This is because the group can be specified, and the encrypted code string can also be used as an identification (ID) code to identify each sub-group, so when setting up a frequency fee system where the fee changes depending on the degree of use. It is especially convenient for

Further, in such a case, the company operating and managing the communication system may use the communication device 1 for its own system management. Now, it is 1 in Figure 2.
If it is a communication device IS installed on the floor, this communication device IS has a code assigned to each communication device 1 so that it can access all communication devices 1... What is necessary is to store encoded code string patterns and configure each communication device to be selectively callable by a polling signal or the like.

In addition, apart from the communication contents of each communication device 1..., when the information management company 64 established in an area distant from each building 60 wants to monitor the usage frequency and status of the communication device. In particular, as separately proposed by the present applicant, each communication device 1 is attached to each device, for example, information obtained from various devices installed in a building, such as vending machines, etc.
If you want to obtain the information at the information management company 64, which is also established separately, after collecting it with the communication device IS as an information collection station in the building, for example, It is preferable that the communication device IS serving as the information collection station and the communication device 4 installed in the information management company 64 be communicably connected using the public telephone network 3.

A similar idea is that the information group collected by the information management company 64,
Depending on the content or type, it can also be developed into a system that selectively sends the various information to each user 65 who uses it. In such a case, a system installed within the information management company 64 The communication device 4 and the communication device 5 installed in each user 65 may be communicably connected via the public telephone line network 3.

Of course, such a system can be applied to multiple buildings 60, although only one is shown in FIG.

However, in such a case, there are two possible communication modes between the communication device IS in each building and the communication device 4 in the information management company 64.

First, in each building 60, encryption processing of transmitted data and spread spectrum modulation are used together in accordance with the basic method of the present invention. The communication mode sent to the communication device 4 and the communication mode in the opposite direction are also a mode in which encryption processing and spread spectrum modulation are used together,
Secondly, considering the use of the public telephone network 3, which has many restrictions, this signal transmission should be performed with at least demodulated spread spectrum modulation, and the data should be encrypted. It is.

A similar argument can be made when the information management company 64 further uses the public telephone network 3 to provide information to the user 65.

In such a system, each communication device Is,4
．． The concept of the internal configuration required for 5 is as shown in Figure 3.4, for example.

FIG. 3 shows an example of the main components of a communication device IS that is installed in a building 60 and is communicably connected to a communication device 4 as an external communication device via a public telephone line 3. As shown in FIG.

Encrypted data subjected to spread spectrum modulation sent from any other communication device 1 (FIG. 2) via a wired signal transmission line 2 such as a power line is sent to that communication system via a coupling device 20. Spread spectrum demodulation is performed by the SS-modem IO according to the spread spectrum method used, and the data is further demodulated by the decoding modulator 3 in the data decoding circuit 34.
3, the data is decoded and taken in as received data, and stored in the memory 41 if necessary.

This kind of operation is generally performed by a microcomputer (CP
For example, if the information issued by each communication device 1 is sales information obtained from a vending machine or other information to be managed, a service person will control the communication device IS as an information collection station. Incidentally, an output device 42 consisting of a suitable display, printout device, etc. may be provided so that information from all communication devices 1 or all devices to be managed can be visually checked.

-Then, the data received as described above is sent to the communication device IS.
When transmitting the data to the public telephone line 3, the switch 53, which is schematically shown as a mechanical contact switch, is connected to contacts T, depending on whether the data is to be encrypted or to be further subjected to spread spectrum modulation. or T2.

Each contact T+ and T2 are a set of two,
They are switched and selected in conjunction with each other, but when transmitting from the communication device IS, the contacts T shown in the upper part of the figure, ,
The data signal passes through either T2.

When the contact T is selected, as can be understood from the fact that it is connected to the output of the SS-modem 10, it is first received under the control of the microcomputer 40 and then stored in the memory 41.
After encrypting the stored data using the encryption circuit 32, it is further subjected to spread spectrum modulation, and then transmitted from the telephone line modem 51 to the line connection unit (NCU) 5.
2, the encrypted spread spectrum modulated data is sent to the public telephone line 3 in an appropriate modulation form.

On the other hand, when the contact T2 is selected by the switch 53, the data to be transmitted is transmitted to the encryption circuit 32, as understood from the fact that it is connected to the output of the encryption circuit 32.
The encrypted data is then sent from the telephone line modem 5<b>1 to the public telephone line network 3 via the line connection unit (NCU) 52 . Modem 51 for telephone line
and NCU32 are all publicly known and can be easily incorporated into the communication device IS.

The encrypted data or encrypted spread spectrum modulation data sent to the public telephone line 3 in this way is transmitted to the fourth
The information is captured by the communication device 4 installed by the illustrated information management company.

The internal structural concept of this communication device 4 is as follows, except that there is no coupling device 20 for wired signal transmission lines such as power wiring.
The communication device IS is similar to the communication device IS shown in FIG. If the data is encrypted data, it is applied directly to the decoding circuit 33 by selecting contact T2, and if it is encrypted spread spectrum modulation data, it is applied to the input of the SS-modem IO.

In this way, the CPU 40 (however, the more communication devices it manages, the larger the capacity compared to the micro computers, etc. installed in communication devices 1.IS installed in each building). Through the intervention of the operation of memory 4
1 or output the received data to a suitable output device 42.

Conversely, from the communication device 4 installed in the information management company 64 to the communication device IS installed in each building 60, the public telephone line 3
The same operation occurs when sending information using . When transmitting data from the communication device 4 as encrypted data, contact T2 is selected, and the communication device IS also selects contact T2 and performs encrypted spread spectrum modulation. When sending out data, this communication device 4 and the in-building communication device! It is sufficient to select the contact point T1 on both sides of S. The signal flow is already self-explanatory.

Further, the circuit configuration shown in FIG. 4 can also be applied to the communication device 5 installed in each user 65 communicably connected to the information management company 64 via the public telephone line 3. That is, if there are two communication devices shown in FIG. 4, one of them is considered to be installed at the information management company 64, and the other one is installed at the user 65, so that transmission can be performed as necessary. By encrypting the data to be transmitted or by applying spread spectrum modulation, it becomes possible to communicate with each other via the respective telephone line modems 51 and 51 and the NCUs 52 and 52, and eventually within each building 60. It is possible to construct a relative communication system as shown in the second diagram, which also includes each communication device 1 installed in the second figure.

Of course, if it has not been determined whether the communication mode between each communication device regarding the public telephone line 3 should be limited to sending and receiving encrypted data or whether spread spectrum modulation should also be applied, The switch 53 used for the schematic explanation is unnecessary, and fixed wiring may be provided on any suitable contact line side.

Even in such a system system, encryption is applied in combination with spread spectrum modulation for the wired signal transmission line section (in this example, the power wiring system in the building) where there is a high possibility of information being damaged. As long as the code string is adopted, it can also be used as an appropriate identification code, so for example, the information management company 64 can use this code string to identify each building 60 or each user 65, and the billing system This is particularly advantageous when constructing. Needless to say, the original function of information concealment is effectively demonstrated.

Further, in a system as shown in the second diagram, the communication mode may be changed between the building 60 and the information management company 64 and between the information management company 64 and each user 65.

One may further perform spread spectrum modulation on encrypted data, and the other may transmit and receive encrypted data.

Furthermore, if the communication device IS shown in the building 60 only needs to serve as an information relay base, the data encryption circuit 32, the decryption circuit 34, or even the data encryption circuit 34 in FIG. SS-modem IO may also be unnecessary. In other words, any communication device in building 60! If the encrypted spread spectrum modulation data obtained from the SS-modem 10 is to be spread spectrum demodulated but not decoded, the output of the SS-modem 10 may be supplied to the telephone line modem 51.
Similarly, the encrypted data obtained from the external communication device 4 is
- Spread spectrum modulation at modem IO and coupling device 2
0 to the communication device 1, or if it is to be transmitted to the public telephone line 3 as it is with spread spectrum modulation, the output of the coupling device 20 is directly applied to the telephone line modem 51, and the output from the modem 51 is The encrypted spread spectrum modulation data obtained may be directly superimposed on the wired signal transmission line 2 from the coupling device 20.

Naturally, the memory 41 and the output device 42 are also unnecessary.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the main parts of an example of a communication device configured to be suitable for the communication method of the present invention. FIG. 2 is a schematic configuration diagram of an example of a communication system that can be constructed using the present invention. FIG. 3 is a schematic diagram of the main parts of an example of a communication device configured to be connectable to a public telephone line network. FIG. 4 is a schematic configuration diagram of main parts of an example of a communication device that can communicate only via the public telephone line network. FIG. 5 is a schematic configuration diagram of main parts of a configuration example of a communication device that employs a conventional spread spectrum modulation/demodulation method. It is. In the figure, 1. Is, 4.5 is a communication device, 2 is a wired signal transmission line such as an in-building power line, 3 is a public telephone line network, IO is a spread spectrum modulation/demodulation circuit or SS-modem, 11
is a PN code string generator for spread spectrum modulation and demodulation, 12
13 is a balanced modulator, 13 is a carrier fc oscillator, 14 is a modulator, 15 is a modulator that functions as a mixer, 16 is a balanced modulator that functions as a spread spectrum demodulator, 20 is a coupling device, and 30 is a data encryption circuit. , 31 is an encrypted code string generator, 32 is an encrypted modulator, 33 is a data decoder, 3
4 is a data decoding circuit, 40 is a computer, 41 is a memory, 42 is an output device, 60 is a building, 64 is an information management company, and 65 is a user of the provided information. Applicant Kurita Industries Co., Ltd.

Claims (5)

[Claims] (1) On the transmitting side, after modulating the transmitted data with a cryptographic code string, the encrypted data is further spread spectrum modulated, and the spread spectrum modulated data is superimposed on the wired signal transmission line via a coupling device; Then, the encrypted data subjected to spread spectrum modulation is received via a coupling device coupled to the wired signal transmission line, and after spread spectrum demodulation, the encrypted data is decoded using the encryption code string. , read as received data; a wired communication method characterized by: (2) A method of mutual communication using a wired signal transmission line between at least two or more communication devices; each communication device is provided with a transmitter and a receiver; the transmitter of each communication device After modulating the transmission data with a cryptographic code string, the encoded data is further spread spectrum modulated, and the spread spectrum modulated data is superimposed on the wired signal transmission line via a coupling device; The receiving section receives the encrypted data subjected to spread spectrum modulation via a coupling device coupled to the wired signal transmission line, performs spread spectrum demodulation, and then converts the encrypted data using the encrypted code string. A wired communication method characterized by: decoding the above-mentioned transmission data issued by each other communication device as reception data. (3) At least two or more communication devices are connected to each other via a wired signal transmission line installed in one building; The at least one communication device is communicably connected to another external communication device via a public telephone network; the communication device in the building connected to the external communication device transmits spread spectrum modulated encrypted data. 3. The wired communication method according to claim 2, further comprising: transmitting the signal in its spread spectrum modulated state to the external communication device via the public telephone line network. (4) While at least two or more communication devices are connected to each other via a wired signal transmission line wired within one building; The at least one communication device is communicably connected to another external communication device via a public telephone network; the internal communication device connected to the external communication device transmits the spread spectrum modulated encrypted data to the 3. The wired communication method according to claim 2, further comprising: transmitting the encrypted data as it is to the external communication device via the public telephone line network without performing the decoding after the spread spectrum demodulation. (5) The wired signal transmission line is a power line installed and wired in a building; The wired communication method according to any one of claims 1 to 4.