JPH05504027A - Method and apparatus for providing confidentiality/security in communication systems - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Method and apparatus for providing confidentiality/security in communication systems Amount of freight released TECHNICAL FIELD The present invention relates to communication systems, and in particular to communication systems including wireless transmission links. It concerns the stem.

Due to recent improvements in the environment and advances in computer and communication circuit technology, performance - Significant progress has been made in personal and business communications.

Multiple companies compete with American Telegraph and Telephone Corporation (AT&T) in the long-distance telephone market. improved maritime radio telephone services and public access on airplanes and trains. Major changes are occurring in current services, such as the provision of public telephone services. ing. In addition, cellular telephone service and radio positioning satellite service (RDS) S: Radio Determination 5atellite 5erv Completely new services are also being used by communication users, including ice.

These new and improved services bring convenience to telecommunications users. , is helpful. However, many such services 0 For example, , maritime radio telephone lines can be easily tapped by all other maritime radio telephone users. and also by owners of commercially available and readily available scanning receivers. It is well known that it can be intercepted. Communication via cellular phone is also in the UHF band. Scan like many older television sets with the ability to tune to channel 82 of It is not widely known that standard receivers can easily intercept Many long-distance calls made through standard long-distance carriers are transferred to satellite lines or terrestrial lines. To transmit several points through a wireless link such as a microwave relay line on is also not widely known - somewhere between the station on the line and the station immediately following it, Microwave receivers installed on transmission lines such as 0 communication line that allows you to monitor the content of communications conducted over such lines. The technology to provide secrecy still exists and is built into wireless links. for example , scrambler/descrambler units are commercially available, and It can be added to standard telephones to communicate with cellular telephones. Such systems are used by telephone companies Scrambler/descrambler unit Confidential calls could only be made with landline telephones equipped with

Other systems using advanced cryptography ensure that the called party's phone is equipped with a decryptor. Allows you to make calls from one cellular phone to any fixed telephone without the need for It is Noh. Such a system is provided by Lopinto, for example. No. 4,549,308. However, such systems require interconnection with and modifications to telephone company equipment. , it was not something that users could utilize immediately.

Methods and methods for ensuring confidentiality of communications via lines with wireless links It would be desirable to provide a system for this purpose. Additionally, each called telephone has an additional For calls from one car phone to any called phone without the need to install equipment. It would be desirable to provide a method and apparatus that allows confidential communication even when functions of a telephone company or other service company (Co+u+on carrier) It is desirable to achieve this with minimal changes to the equipment provided by s), and , the confidentiality of communications depends on the sensitivity of the information being communicated and how much money is being spent. It is desirable to provide a function that allows the level of anonymity to be selected.

Hatsudara Ω summary The objects and advantages of the invention will be explained, in part, below, and in part by way of the following description. Such objectives will be apparent from the and effects may be achieved by means of devices and combinations particularly pointed out in the appended claims. can be manifested and achieved.

The present invention is necessary for existing equipment owned by telephone companies or cellular telephone companies. By providing a scrambler/descrambler that minimizes changes It overcomes the problems and shortcomings of the prior art. Further, realizing the present invention The device may be owned and controlled by the user of the communication system and may be attached to the user's equipment. Can be attached. Such equipment is intended only for use with standard subscriber telephone lines. can be connected to telephone company equipment.

In accordance with the purpose of the present invention and in order to achieve the above-mentioned aims, the invention is hereby realized and extensive. used to couple the first and second communication channels, as described in communication system secrecy device is provided. This device is designed to protect a diverter for setting up a communication path between the first and second channels according to the signal; The apparatus further includes first and second terminals, the apparatus further having first and second terminals; a second terminal for encrypting the received signal and providing the encrypted signal to the first terminal; decodes the signal received from the first terminal and transmits the decoded signal to the second terminal. Contains encryption means for providing. Finally, the device responds to the activation signal to , the first terminal is connected to the first channel, and the second terminal is connected to the second channel. coupling means for selectively connecting the encryption means to the diverter means so as to the encrypted signal received from the first channel is transmitted to the second channel. a signal transmitted in decrypted form over a channel and received from a second channel is transmitted over the first channel in encrypted form.

In another aspect, the invention provides a communication system having first and second channels. This method provides a method for providing secrecy in one of the channels. receiving a first activation signal via one; and in response to the first activation signal; receive communication signals from the channel, and in response to communications received over this channel. , forming a communication path between the first channel and the second channel, through the channel selectively inserting an encryption/decryption circuit into the communication path in response to a received communication signal; The method includes the steps of: decoding the communication signal and transmitting the decoded signal over a second channel; encrypt the signal received through the first channel and encrypt the signal through the first channel. and a final step of transmitting the second channel signal.

In yet another aspect, the invention provides a first, a second, and a third communication channel. It provides a security device for communication systems used to connect 0 The device is configured to respond to signals received via one of the first and second channels. Accordingly, a first channel for forming a communication path between the first channel and the second channel. diverter means and received via one of the second and third channels. for forming a communication path between the second channel and the third channel in response to a signal transmitted from the second channel to the third channel. second diverter means for each encrypting the signal received from the second terminal; , for providing the encrypted signal to the first terminal; a first terminal for decoding the signal received from the terminal and providing the decoded signal to the second terminal; and first and second encryption means having a second terminal. This point The invention further provides that, in response to the activation signal, the first terminal of the first encryption means is activated. a second terminal of the first encryption means connected to the second channel; selectively connecting the first encryption means to the first diverter means such that the first encryption means is connected to the first diverter means; and a first coupling means for coupling. Finally, in response to the activation signal, the present invention a second terminal of the second encryption means is connected to the third channel; the second encryption means is connected to the second adapter such that the first terminal is connected to the second channel; a second coupling means for selectively connecting to the inverter means; the signal received by the device from the first channel is transmitted via the second channel. sent in encrypted form and retransmitted decrypted via a third channel. and the signal received by the device from the third channel is in encrypted form. transmitted over a second channel in a decrypted state and transmitted over a first channel in a decrypted state. will be resent.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate illustrative embodiments of the invention. are illustrated, and together with this description, serve to provide a detailed explanation of the invention.

Concave dish Φ prison rate star theory■ FIG. 1 is a block diagram of a communication system incorporating a preferred embodiment of the present invention. be.

2A and 2B are more detailed block diagrams of one embodiment of the invention shown in FIG. be.

Figures 3A and 3B illustrate the bypass and interface circuits of the device shown in Figure 2. FIG.

Figure 4 is a system diagram showing the relationships between various signals and operations in the system of Figure 1. FIG.

FIG. 5 is a block diagram of a second, more preferred embodiment of the present invention.

It's good°-'H In the following, a detailed description of the invention will be given with reference to more preferred embodiments of the invention and its implementation. The examples are illustrated in the accompanying drawings, where like elements have corresponding references throughout the drawings. They are numbered and explained.

FIG. 1 depicts a cellular telephone system 10 incorporating a more preferred embodiment of the present invention. are doing. System 10 includes a plurality of standard cellular telephones, such as cellular telephone 12. 0 For example, a cellular phone may include Motorola, Schaumburg, Illinois. It may be a cellular radio telephone model 760 commercially available from LA Corporation. . As is well known to those skilled in the art, cellular telephones use multiple frequencies. Dual Tone (D T M E: Dual Tone I’lul ti telephone connected to a push-button dial unit Includes a handset, radio transmitting and receiving circuitry, and associated control circuitry. cellular - Usually located in the car, the phone is equipped with a small, lightweight hand belt unit. It may also be configured as a set.

As seen in FIG. 1, cellular telephone 12 is scrubbed by lines 16 and 18. It is connected to the scrambler/descrambler unit 14. scrambler/desk Rambla 14, for example, is located at Cellular One (Ce) in Greenbelt, Maryland. M frequency inversion type scrambler/descrambler commercially available from A model 1905 crumbler unit may also be used.

Cellular telephone 12 has a bidirectional radio link shown schematically at 22. A cell communicating with a cell site 20 of a ms-like cellular telephone system via a - The site 20 has a transmitting/receiving circuit that enables full duplex communication with the cellular telephone 12. Contains roads. Cell site 20 is a rented 4-wire telephone line and fiber optic cable. , or to a mobile telephone exchange 23 by known means 22 such as a microwave link. Connected. The mobile telephone switching center 23 uses known means 24 (return) from cellular systems. cables, leased 4-wire telephone lines, fiber optic cables, etc.) Connection to the public switched telephone network and to the local telephone company's central office switch 26 Bring on the connection.

In a more preferred embodiment, the present invention couples the first and second communication channels to Provides a communication system concealment device including a base module 28 used for It is something to do. As implemented herein, the first and second communication chaffles are interchangeable. It includes standard two-wire telephone lines L1 and L2 connected to switch 26.

Lines L1 and L2 are each numbered in the same way as all standard telephone lines. I'm being kicked.

The present invention provides a first and a second channel in response to a signal received over the channel. and includes diverter means for forming a communication path between the two. realized here Such a diverter means is called a call diverter, as in verter) 30. Further, the present invention also provides a method for receiving signals from a second terminal. for encrypting the signal and providing the encrypted signal to the first terminal; decoding the signal received from one terminal and providing the decoded signal to the second terminal an encryption means having first and second terminals for the encryption; realized here As shown, such encryption means has a first terminal 31 and a second terminal 33. The encoder/decoder unit 32 includes an encoder/decoder unit 32. Scrambler/descrambler Knit 32 is available from Cellular One, Greenbelt, Maryland, for example. Model 19 of frequency inversion type scrambler/descrambler unit 05B is fine.

The invention further provides that, in response to the activation signal, the first terminal is connected to the first channel; the encryption means to the diverter means such that the second terminal is connected to the second channel; coupling means for selectively connecting the first channel to the first channel; The received encrypted signal is sent decrypted via a second channel. and the signal received from the second channel is encrypted via the first channel. Sent in state. As realized here, such a coupling means A bypass interface circuit 34 is included. More preferably, the coupling means The first mode in which the encryption means on the communication path is isolated from the communication path, and the first mode in which the encryption means on the communication path are isolated from the communication path. and a second mode connected in series with the signal path.

Latin L1 and L2 are coded by vj, which will be explained in more detail below. A bypass multiplexer 35 is connected to the bypass multiplexer 35 via a loop diverter 30. Than Preferably, the diverter means is responsive to the presence of a DTMF signal on the communication path. , DTMF detection means for generating a DTMF detection signal. fruit here As illustrated, the DTMF detection means includes a diverter control circuit 44 (FIG. 2A). I'm reading.

More preferably, the coupling means does not operate while the DTMF signal is present on the communication path. and means for maintaining the first mode in the first mode. as realized here , the maintaining means is a timing/control circuit 3 controlling the bypass multiplexer 35. Contains 6. Bypass multiplexer 35 is a scrambler/descrambler The unit 32 is a call diverter 30 and a scrambler/descrambler 32. , call diverter 30, and a first position connected in series to line L2. have a version. In the second position, bypass multiplexer 3 5 isolates the scrambler/descrambler 32 from the communication path. Scrambler/ A descrambler 32 is connected in series in the communication path by a bypass multiplexer 35. When connected, bidirectional full-duplex communication is provided by the transmitter/receiver circuit 38.40. Ru.

An overview of the operation of system 10 including base module 28 will be described. User selects cell Make a call in the usual way from the telephone line L12 and dial the telephone number of the telephone line L1. file. Cellular telephone 12 then communicates with cell site 2 via wireless link 22. 0, and via cable 22 to mobile telephone exchange 23, cable 24, and A line is set up to telephone exchange 26 to line L1, and a ringing signal is placed on line L1. cause it to occur. Call diverter 30 recognizes the ringing signal on line LL; Take line L1 off-hook, i.e. call diverter 30 "Responds" to the input L1.

At this point, call diverter 30 connects to cellular phone 12 via line L1. When a user calls cellular phone 1 by generating an access code request tone that is transmitted, prompt to send the access code using the DTMF dialing unit 2.

The DTMF component that constitutes the transmitted access code is call diverter 3. 0 and the transmitted access code is programmed into call diverter 30. If it matches the access code input from the RAM, line L2 is off-hook. and line L1 is connected to line L2 by call diverter 30. . The transmitted access code is programmed into the call diverter 30. If the access code does not match the access code entered, call diverter 30 diverts line L1. on-hook, that is, call diverter 30 puts line L1 on “ Set the handset to ``M (harg up)'', and then the cellular The telephone 12 terminates the call. Please note that the use of access codes is optional. Then, when line L1 is taken off-hook, call diverter 30 Unconditionally set line L2 to off-hook state and connect line L1 to line L2 line L2 is taken off-hook by call diverter 30. A dial tone is generated by the telephone exchange 26 when the call is made. this diamond The line tone is received by call diverter 30 via line L2 and via link L1 to telephone exchange 26, mobile telephone exchange 23, and cell site 20. is sent back to the cellular telephone 12 via. When the user dials from line L2 - When a tone is received from the cellular telephone 12, the user connects to the switched regular telephone line. desired to make a call to the desired phone that is accessible via Sotowork. Dial the phone number.

As long as line L2 remains on-hook, timing/control '4 of circuit 34 1 circuit 36 includes a multiplexer 35 and a scrambler/descrambler 32 inserted. The eight circuits 36 that are placed in the Recognizes the presence of a dial signal on the in-1. Line L2 is off-hook Afterwards, circuit 36 controls multiplexer 35 while the dialing signal is being supplied and Bypassing scrambler/descrambler 32 for a predetermined delay time after Make them stay in position. Once the delay time has elapsed, circuit 36 Activate the plexer 35 and interpose the scrambler/descrambler 32 in the communication path. Close. The user then sends the encrypted signal to the cell service via the wireless link 22. 20, mobile telephone exchange 23, telephone exchange 26 and base module 28. a scrambler/descrambler 1 connected to the cellular telephone 12 to Start 4. The encrypted signal from line L1 is scrambler/descrambler 32 and retransmitted decrypted via line L2 to the called party. be done.

Insert scrambler/descrambler 32 based on DTMF dial signal Instead, the scrambler/descrambler 32 is selected for the communication path by other signals. For example, a sequence of DTMF signals may be In order to insert both scrambler/descrambler units 14 and 32, Can be generated as code. In addition, appropriate scrambler/descrambler design Therefore, no one can pass through both scrambler/descrambler 14 or 32. Scrambler/Descrambler 1 to generate the signal that will be connected to the signal path. Either 4 or 32 can be operated.

In a similar manner, unencrypted signals from the called party pass through telephone exchange 26. and reaches the base module 28 via line L2. Encryption from line L2 The signal that is not encoded is encrypted by the scrambler/descrambler 32. line L1, telephone exchange 26, mobile telephone exchange 23, cell site 20 and retransmitted to cellular telephone 12 via wireless link 22. stop The encrypted signal passes through the scrambler/descrambler 14 and is decoded there. and provided to the user.

In this method, only the encrypted signal is transmitted by the wireless link 22 and the security accessed by a public switched telephone network with a caller using a telephone 12. Confidentiality of the conversation between the called party and the called party in a location where they can be decrypted to the called party's phone. Ensures reliability without the need to attach a device. In addition, telephone companies and service The connection to the company is a normal sign! 1! This is done via telephone line.

Now, looking at Figures 2A and 2B, base module 2 is shown in more detail. Ru. Standard telephone service is commonly brought into homes and offices to provide Line L1, which is a standard two-wire telephone line, connects to call diverter 30. It is continued. In a more preferred embodiment, call diverter 30 is Code-A-Phone Co., Ltd., Boatland, Gon The model 2597 programmable call diverter commercially available from Contains.

Further information regarding programming and operation of the call diverter model 2597. Information on the model 2597 service available from Code-A-Phono Co., Ltd. Found in Mannar 11 [#9970660.

Line L1 is a line 1 selection signal 42 generated by the diverter control circuit 44. is connected to relay S31 under the control of. The ring detection circuit 46 is connected to line L1. It is connected. The ring detector circuit 46 is a standard comparator circuit, with line L1 Monitor the voltage level above and detect the presence of a 16-60Hz ring signal at 90 volts RMS. Once detected, a call-on-line detect logic signal 48 is generated. Call detection times The circuit 46 may be any standard comparison circuit, and its design is subject to the present technology. 1 call detection on the line, which may be within the capabilities of a person of ordinary skill in the field. Signal 48 is provided to divertor control circuit 44 .

A similar call detection circuit 47 is connected to line L2 and detects calls on line 2. When the signal is detected, the line 2 call detection signal 49 is transferred to the diverter control circuit 4. Supply to 4.

The output of relay S3 is connected to a standard 2vA/4-wire hybrid circuit 50. Ru. The hybrid circuit 50 has a function for normal full-duplex communication using this system. Included to bring. The signal received via line L1 is is output as an output by the HiPrint circuit 50 via line 52 of the EAR signal. It will be done. The signal on line 52 is an audio amplifier connected to output terminal 56 in a standard configuration. The signal received via line L1, which is amplified by amplifier 54, is output to output terminal 56. scrambler/descrambler by the method provided and more fully described below. Bypass interface circuit to allow selective interconnection of Pass through 34. The signal received from line L1 is on line 2 microphone signal line 59 is looped back from the bypass interface circuit 34 via the diverter control Relay 32 under control of diverter signal line 57 generated by circuit 44 is supplied to call diverter 30 at input terminal 58 connected to one terminal of It will be done. Further, the diverter control circuit 44 is connected to the bypass interface circuit 34. DTMF detection signal detection signal lifecycle 6 for further use.

The other terminal of relay S2 is connected to the second 2-wire/4-wire hive via the continuation of line 59. It is connected to one of the four-wire terminals of the lid circuit 60. 2 microphone signals on line passes through hybrid circuit 60 to relay 54 and is retransmitted via line L2. It will be done. Relay 34 receives two selection signals on the line generated by diverter control circuit 44. It is controlled by the number line 62.

The signal received from line L2 forms the line L2EAR signal on line 64. passes through relay 54 and hybrid circuit 60 in order to Faith on line 64 The signal is routed through a standard audio amplifier 66 and an output terminal 68 to a bypass interface. selective interconnection of the scrambler/descrambler 32 to a base circuit 34; Used in connection with. The line L2EAR signal is the control on divert signal line 57. After that, the light passing through input terminal 70 connected to one terminal of relay S1 is is looped back from the bypass interface circuit 34 as a LIMIC signal. . The other terminal of relay 31 is connected to line 74. The signal on line 74 is It is retransmitted via line L1 through hybrid circuit 50 and relay S3.

In the bypass interface circuit, the on-line 2 selection signal 62 is connected to the control circuit. More preferably, circuit 36 is a multiplexer circuit. The coupling means is operated in a second mode for a predetermined period after detection of the DTMF signal on the communication path. As implemented herein, including means for causing the switch to These means include a start delay Dutch 80, an encoder deactivation one-shot circuit 90, and an encoder deactivation one-shot circuit 90. 84. Signal 62 is latched through inverter 7 80 is supplied to a first terminal 81 of the terminal 80 . DTM detection signal 76 is connected to the second Connected to terminal 83. The output of latch 80 is the encoder activation/multiplexer control signal. 82, which controls multiplexer 84. The multiplexer 84 is Logic high level signal 86 or code provided from the power supply for circuit 34 Delayed encoder signal 88 generated by encoder one-shot circuit 90 is selected as the output of multiplexer 84 to form the encoder enable signal 92. The connection will be made automatically. The trigger input of the one-shot circuit 90 is DTMF detection. signal detection signal is activated.

Encryptor enable signal 92 is also applied to Provided as a control signal for path multiplexer 35. multiplexer 35A and 35B each include one supply terminal and a pair of selected terminals. I'm here.

The bypass interface circuit 34 also includes four level adjustment amplifiers 94A, 94B, 94C1 and 94D and four universal interface circuits 9 Contains 5A, 95B, 95C195D. Multiplayer as shown in Figure 2 Selected terminals of crossers 35A and 35B are connected to amplifiers 94A, 94B, 94, respectively. Connected to one terminal of C1 and 94D. Amplifiers 94A, 94B, 94 The other terminals of C1 and 94D are connected to interface circuits 95A, 95B, Connected to one terminal of 95C2 and 95D. Interface circuit 9 The other terminals of 5A, 95B, 95C2 and 95D are each scrambler/desscrambler. PH0NSET EAR, HANDSET EARl of crumbler unit 32 Connected to the PHONSET MICl and HANDSET MIC terminals. Ru.

As shown in FIG. 2B, the line 1 EAR signal line 52 is connected to the input of amplifier 94A. and one selected terminal of multiplexer 35A. Line L 2MIC signal line 59 is connected to a common terminal of multiplexer 35A.

Line IMIC signal line 75 is connected to the common terminal of multiplexer 35B. and line 2EAR signal line 64 is the input and multiplexer of amplifier 94D. It is connected to the selected terminal of the sensor 35B. Call diverter 30, bypass operation of the interface circuit 34 and the scrambler/descrambler 32. The operation will be explained in more detail with reference to FIGS. 2A and 2B.

For example, a call from the cellular telephone 12 (FIG. 1) to the telephone number on line L1 is made by the user. When a call is placed, a 90 Port RMS, 16-60Hz ringing signal is sent to the telephone company. is supplied to the line L1 by the exchange 26. This signal is the line 1 ringing detection signal. This is detected by the call detector circuit 46 which turns on the signal 48. Diverter system Control circuit 44 detects the presence of the line 1 ring detection signal and causes relay 53 to go high. Turn on the line 1 selection signal to insert the bridge circuit 50 into line LL. do. As a result, line 1 is placed in an off-footer state. Also, the diverter control circuit Line 44 selectively diverts 2 select signal lines 62 on line 9. The control circuit 44 is connected via line 45 to line IMIC signal line 74. , may generate an access code request signal such as a beep tone. uses the DTME dialing unit of the telephone making the call, as described above. line L1 to prompt the caller for an access code rather than using The access code request signal is sent via the access code request signal. And the diverter system When control circuit 44 receives the appropriate access code, it selects line 2 on line 62. The state is such that a signal is generated. The line 1 selection signal on line 62 connects line L2. After being turned on to go off-hook, the divert signal 57 turned on by the diverter control circuit 44 to close S1 and S2; This connects line L1 to line L2. The diverter control circuit 44 relays S1, S2, S3, and S4 in response to the ring detection signal A communication path is formed through the communication circuit 50, thereby receiving data from any of the channels. DTMF signals to be transmitted can now be transmitted via other channels.

Before the line 2 select signal on line 62 is activated, inverter 7 causes latch 8 to A reset signal was continuously generated at the 0 terminal 81. In this way, the dark signal enable control signal 82 is deactivated and a logic high signal is sent to multiplexer 84. 86 is connected to the encoder activation line 92. This allows multiplexer 35A and 35B are line IEAR signal line 52 and line L2MIC signal line 5. 9, line L2EAR signal line 64 is connected to line IMIC signal line 7. 4, as shown in Figure 2, and the scrambler/descrambler The scrambler/descrambler unit 32 is bypassed and the scrambler/descrambler unit 32 is bypassed. This results in isolation of the port 32.

When the on-line 2 selection signal 62 is turned on, relay S4 turns off line L2. Set to hook state. Then, the telephone company's exchange 26 (Figure 1) connects line L2E. to line L1 via AR signal line 64 and line IMIC signal line 74. The dial tone from line L2 is retransmitted to the caller on cellular telephone 12. to receive. The caller then uses a DTMF dialing unit to Dial the number of the desired called telephone.

The circuit 90 remains inactive for up to 10 seconds after the last DTMF signal from the cellular telephone 12. To disconnect the scrambler/descrambler from the communication path, use the scrambler activation signal. No. 92 remains logic high. Thus, circuit 90 connects multiplexer 84 Configure a timer circuit connected to the selected terminal of. Commercially available call diver In a more preferred embodiment using a converter, the function of the diverter control circuit 44 is as follows. It is done by a microprocessor. However, the experts in this technology do not understand. As shown, the function of the diverter control circuit 44 is a discrete analog and For example, the DTMF detection signal 76 can also be realized by a digital circuit. Teltone Corp., Kirkland, Washington Standard TM such as M-957 type commercially available from Ora~tion) It can be generated by a Fljl tuning circuit.

In some applications, a landline telephone may be connected to a cellular telephone 12 using module 2B. It is desirable to be able to make secret calls to Certain changes are made to the programming of the inverter control circuit 44. In particular, divers The controller control circuit 44 closes the relay 54 to place line L2 in an off-footer condition. , by activating the 2 selection signal on the signal line, the call detection 2 signal 49 is activated. programmed to respond. Access code is distinguishable on line 2 This can be selectively requested by the caller by generating a tone. Wear. The user then receives access by sending a sequence of DTMF signals. You will be expected to send a code. These signals are received by divertor signal 44. The DTMF signal is transmitted, demodulated, and held within the diverter control 44. compared to data representing a sequence of . If the comparison matches, access as appropriate. - This indicates that the code has been sent.

The appropriate °access code is entered or no access code is requested. If not, the diverter control circuit closes relay S3 and takes line L1 off-hook. In order to do this, the line L1 selection signal 42 is activated.

The diverter control circuit 44 displays data previously held in the diverter control circuit 44. generates a DTMF dialing signal representing the telephone number of the cellular telephone 12 from the signal is transmitted via line L1. This allows cellular connection via line L1. A call is made to telephone 12. The diverter control circuit 44 connects the line LL to the line L2. The die heart signal 57 is activated to connect to. Diverter control circuit 4 After a delay period following the last DTMF signal generated by The interface circuit 34 connects the scrambler/descrambler 32 to line L1 and line L1. Connect in series to the communication path of input L2.

The user answers the cellular phone 12 and activates the scrambler/descrambler 14 Then, both parties communicate via the communication path. When either party picks up the receiver , the diverter control circuit 44 selects line L1 to concentrate the calls. 42, on-line 2 select 62, and divert 57 signals are deactivated.

A landline phone can make calls to anyone, not just a cellular phone12. In this case, the caller should be able to dial the number on line L2. I want to hear it. The diverter control circuit 44 receives the line 2 paging detection signal 4 as described above. 9 is received, line L1 selection 42, line 2 selection 62, and divert 57 Activate the signal. The dial tone from line L1 is returned to the caller. Ru. To dial the cellular telephone 12, the diverter control circuit 44 dials the DTM Instead of generating an F signal, the caller uses the DTM signal to dial the desired caller. Generate F signal. This call is also completed and terminated in the same manner as described above.

Referring now to Figures 3A and 3B, a detailed description of the bypass interface circuit is shown. A diagram of the main parts is shown. The input terminal 100 of the level adjustment amplifier 94A is a cold from the amplifier 54 of the call diverter 30 to the terminal 56 of the call diverter 30. The input terminal 100 receiving the signal line 52 is connected to one end of the resistor 102, and its The other end is connected to the inverting terminal of the operational amplifier 104. Non-inverting operational amplifier 104 The terminal is connected to one end of the resistor 106, and the other end is connected to a circuit common point. resistance The purpose of 106 is to balance the inputs of op amp 104. resistance 10 The purpose of step 2 is to set the input resistance of the operational amplifier 104, which determines the gain of the amplifier 94A. Is Rukoto. The output of the operational amplifier 104 is connected to the variable resistor 11 via the feedback resistor 108. Connected to one end of 0. The other end of variable resistor 110 is the inverter of operational amplifier 104. connected to the terminal. The purpose of the variable resistor 110 is to connect the call diverter 30 and screen. The au pair for appropriate signal conditions to and from the rambler/descrambler unit 32. This is to adjust the gain of the amplifier 104. Operational amplifier 104 is made by Signetic. MC14 commercially available from (Signics Corporation) may include one-half of the 58 types.

The output of operational amplifier 104 is connected to transformer 1, which may be included within interface circuit 95A. It is also connected to one end of the primary winding 112 of No. 14. -The other end of the special winding 112 is a circuit Connected to a common point. Transformer 114 is a handset microphone connector. The secondary winding 118 is connected to the terminal 122 . Transformer 114 is bypassed ・Connect the interface circuit 34 to the scrambler/descrambler unit 32 500 ohm to 500 ohm impedance matching used for It is a transformer. Handset microphone connector 122 is a bypass in provides input from the interface circuit to the scrambler/descrambler unit 32. I'm offering it.

The output of the scrambler/descrambler 32 is used to control the bypass circuit 34. back to the primary winding 126 of the transformer 130 via the von Sent transmit connector 124. be done. Transformer 130 controls scrambler/descrambler unit 32. 1000 ohm to 1000 ohm impedance used to connect to pass circuit 34. - It is a transformer of dance matching. One end of the transformer 130 is connected to the circuit common point. It has a secondary winding 134 whose other end is connected to one end of a resistor 136.

The other end of resistor 136 is connected to the inverting terminal of operational amplifier 138. operational amplifier The non-inverting terminal of 138 is connected to one end of resistor 140, and the other end is connected to the circuit common point. It is continued. The purpose of resistor 140 is to balance the inputs of op amp 138. That is. The purpose of the resistor 136 is the operational amplifier 13 that determines the gain of the amplifier circuit 94B. 8 input resistances. The output of the operational amplifier 138 is the feedback resistor 144 It is connected to one end of the feedback resistor 142 via. The other end of the variable resistor 142 is an operational amplifier. is connected to the inverting terminal of pin 138. The purpose of the variable resistor 142 is a call diver. the appropriate signal state between the controller 30 and the scrambler/descrambler unit 32. The purpose of this is to adjust the gain of the operational amplifier 138 for the following reasons. The operational amplifier 138 is May contain one-half of MCI458 type commercially available from Gnetix .

Also, the output of the operational amplifier 138 is connected to the selected output of the analog multiplexer 35A. Connected to terminal "B". The selected terminal “A” of multiplexer 35A is It is connected to the input terminal 100. The common terminal of multiplexer 35A is line L. 2MIC signal line 59 connected to terminal 5 of call diverter 30. ing. The purpose of multiplexer 35A is to This is to bypass the scrambler/descrambler unit 32. Multiplayer The Kusa 35A is an analog multiplexer available from Ngnetics. I (may contain one-third of the EF4053B type).

Input terminal 200 of amplifier 94D is connected to terminal 68 of call diverter 30. , receives a signal from amplifier 66 of call diverter 30 via line 64. . The input terminal 200 is connected to one end of a resistor 202, and the other end is connected to an operational amplifier 206. is connected to the inverted terminal of The non-inverting terminal of the operational amplifier 206 is one of the resistors 204. The other end is connected to a circuit common point. The purpose of resistor 204 is to The purpose is to balance the inputs of the operational amplifier 206. The purpose of resistor 202 is an amplifier Setting the input resistance of the operational amplifier 206 determines the gain of the 94D. O The output of the operational amplifier 206 is connected to one end of a variable resistor 210 via a feedback resistor 208. It will be done. The other end of the variable resistor 210 is connected to the inverting terminal of the operational amplifier 206. variable Resistor 2100 purpose is call diverter 30 and scrambler/descrambler Adjust the gain of op amp 206 for appropriate signal conditions between That's true. The operational amplifier 206 is MC1 commercially available from Signetics. 2/1 of the 458 type amplifier circuit.

The output of the operational amplifier 206 is connected to one end of the primary winding of the transformer 214, *212. ing. The windings of the primary winding 212 are connected to a circuit common point. transformer 214 comprises a secondary winding 218 connected to a phoneset receive connector 222. There is. Transformer 214 connects control bypass circuit 34 to a scrambler/descrambler. 500 ohm to 500 ohm impedance used to connect to the knit 32 It is a dance matching transformer. The phone set receiving connector 222 has a control bar. provides input from the IP address 34 to the scrambler/descrambler unit 32. .

The output of scrambler/descrambler unit 32 is connected to the primary winding of transformer 230. Handset earphone connector 2 of interface circuit 95C to 226 24 to the control n bypass circuit 34. Transformer 230 is a scrambler /Kernel of the bypass circuit 34 that controls the descrambler unit (I[ernel ) 1000 ohm to 1000 ohm impedance used to connect to the H path. - It is a transformer of dance matching. One end of the transformer 230 is connected to the circuit common point. The secondary winding with the other end connected to one end of the resistor 230! It is equipped with 232. resistance The other end of resistor 236 is connected to the inverting terminal of operational amplifier 240, which forms part of amplifier 94C. Connected.

The non-inverting terminal of operational amplifier 240 is connected to one end of resistor 238, and the other end of that resistor is connected to the circuit common point. The purpose of resistor 238 is to vary the input of operational amplifier 240. It is important to take a good stance. The purpose of resistor 236 is to act as an op pair to determine the gain of the amplifier circuit. setting the input resistance for amplifier 240.

The output of the operational amplifier 240 is connected to one end of the variable resistor 242 via the feedback resistor 244. has been done. The other end of the variable resistor 242 is connected to the inverting terminal of the operational amplifier 240. There is. The purpose of variable resistor 242 is call diverter 3o and scrambler/desk. Use of operational amplifier 240 for appropriate signal conditions to and from rambling unit 32 It is to adjust the profit. The operational amplifier 240 is commercially available from Signetics. MC1458 type amplifier circuit.

The output of the operational amplifier 240 is also connected to the selection terminal "B'" of the multiplexer 35B. ing. Select terminal 8' of multiplexer 35B is connected to input terminal 200. Ru. The output of multiplexer 35B is connected to call diverter 30 via terminal 70. It is connected. The purpose of multiplexer 35B is to generate a DTMF dial tone. It is to bypass the scrambler/descrambler unit during raw time.

Multiplexer 35B is a HEF4053 commercially available from Signetics. Contains one-third of the B type multiplexer circuit.

Input terminal 300 receives the on-line 2 select signal from terminal 68 of call diverter 30. Receive 62. The input terminal 300 is connected to both input terminals of a two-man NAND gate 302. It is connected. The purpose of the NAND gate 302 is to condition the 2 selection signals on the line. It is configured as an inverter 78 for this purpose. NAND gate 302 is a signature It may contain one-fourth of the 7400 type logic circuits available from S.A.

The output of the NAND gate 302 is a timer 304 configured as a latch circuit 80. Connected to the glue cent terminal. Also, the output of the NAND gate 302 is NAND It is connected to one input terminal of D gate 306. The purpose of this connection is for NAND games. This is to selectively activate the port 306. Timer 304 is Signetics It may contain one half of the 5A556 type timer circuit available from the company.

Input terminal 400 receives DTMF detection signal 76 from call diverter 30 . Input terminal 400 is the second input terminal of MAND gate 306, capacitor 310 , a resistor 312 , and a capacitor 314 . capacitor 310, the resistor 312, and the other end of the capacitor 314 are connected to the circuit common point. There is. Capacitor 310, resistor 312, and capacitor 314 are used for DTMF detection. Signal 760 is provided for conditioning. Output of NAND gate 306 is connected to the trigger power of the timer 304. Timer 304 flips ・Timer reset line and free Equipped with a timer trigger line that works as a set for the top-flop , which operates as a set-recent flip-flop. Structure of timer 304 Since this is the case, the timer 304 will be referred to as "flip-flop 304" from now on. The output of flip-flop 304 is called the A/B selection terminal of multiplexer 84. Connected to child. The purpose of flip-flop 304 is to multiplexer 84 control which of the two inputs of the multiplexer is fed to the output of the multiplexer. That is. When the line 2 selection signal is on, it is a flip-flop 34 and also activates NAND gate 306.

When NAND gate 306 is activated, the signal supplied by call diverter 32 is The next DTMF detection signal sets flip-flop 304 and changes its output state. changes to logic high level.

In addition, the input terminal 400 is one end of a resistor 402 in the encoder deactivation one-shot circuit 90. It is connected to the. The other end of the resistor 402 is connected to the base terminal of the transistor 404. has been done. The emitter terminal of transistor 404 is connected to the circuit common point. Ru. The collector of transistor 404 is connected to one end of capacitors 408 and 410. It is connected. Also, the collector of transistor 404 is the thread of timer 418. connected to the hold and discharge terminals. Capacitors 400 and 41 The other end of 0 is connected to the circuit common point. Transistor 404 is DTMF detection system Each time the control signal turns on, capacitors 408 and 410 are discharged to a common point in the circuit. It is for electricity. Transistor 404 is commercially available from Motorola. It may be of the 2N3904 type. In addition, the collection of the transistor 404 The vector is connected to one end of variable resistor 416 via resistors 412 and 414. Ru. The other end of the variable resistor 416 is connected to the reset line of the timer 418 and the circuit voltage f. i (+5 volts).

Further, the input terminal 400 is connected to one terminal of the NAND gate 406, and the NAND gate 406 is connected to one terminal of the NAND gate 406. The output terminal of the D gate is connected to the trigger input terminal of timer 418. Ta The timer 418 is configured as a one-shot pulse generator, whose pulse width is Resistors 416 and 414, variable resistor 412, and capacitors 408 and 41 Determined by 0. The signal is provided to the trigger input terminal by NAND gate 406. One pulse is initiated at the output of timer 418 when applied. output The pulse is generated by capacitors 408 and 410 at the timer threshold terminals. By the way, the internal threshold level of timer 418 as measured Remains in logic high state until charged to equal voltage level. however The output of timer 418 indicates that the charge on capacitors 408 and 410 is through transistor 404 before reaching the threshold level of charge. DTMF detection signal 76 is turned on, discharging capacitors 408 and 410. remains in a logic high state for as long as the signal remains. Timer 418 is made by Signetinox. It may include one half of the 5A556 type timer circuit commercially available from.

The output of timer 418 is connected to selection terminal "A" of multiplexer 84. . Select terminal "B" of multiplexer 84 maintains terminal "B" in a logic high state. Connected to circuit power supply.

The output of multiplexer 84 is connected to one end of capacitor 320 through resistor 318. has been done. This terminal of capacitor 320 is also connected to the second terminal of NAND gate 406. input terminal and A/B selection control II terminal of multiplexers 35A and 35B It is connected to the. The other end of capacitor 320 is connected to a circuit common point. Ma Multiplexer 84 provides selection control signals for multiplexers 35A and 35B. the timer by supplying and deactivating the signal flow through NAND gate 406. The output of multiplexer 84 provides a return that disables the trigger force to -418. The force signal is connected to a pulse stretching network consisting of a resistor 318 and a capacitor 320. Supplied via. Multiplexer 84 is commercially available from Signetain Inc. It may contain one third of the HEF4053B type multiplexer circuit. Not possible.

When the on-line 2 selection control signal 62 turns ON, the reset signal is removed from drop 304, and NAND gate 306 is activated. but However, the output of the flip-70 flip 304 is when the DTMF detection signal 76 is in the ON state. logic low until it sets the output of the flip-flop to a logic high state. Stay in the U state. When flip-flop 304 goes high, it Set the control signal of the lexer 84 so that the input 1A' is supplied to the output of the multiplexer 84. be provided. Further, the DTMF detection signal is transmitted to the capacitor 4 via the transistor 404. 08 and 410 while triggering washer cover timer 418. Rigger. This causes the output of timer 418 to go to a logic high state. is applied to input "A" of lexer 84. This logic high state is present at multiplexer 84. output and the A/B selection terminals of multiplexers 35A and 35B. , thereby bypassing the scrambler/descrambler unit 32 and from the communication path. Separate it. Circuit 34 connects capacitors 408 and 410 to timer 418. A new DTMF detection signal is called before it is charged to the internal threshold. It remains in this mode while the circuit 34 is being supplied by the ζ diverter 32.

Capacitors 408 and 410 hold the threshold of point timer 418. − level, the timer output switches to a logic low state; This is the A/B selection of multiplexers 35A and 35B via multiplexer 84. Supplied to the select terminal. This logic low state causes multiplexers 35A and 35 B is such that the scrambler/descrambler unit 32 is in series with the communication path 32. Switch. This logic low signal is also pulled back to NAND gate 406 to Deactivates the trigger force of immer 418, resulting in further DTMF detection signal Timer 418 will not be triggered even if timer 418 is on the line 2 selection control line 62 is de-energized until reset from call diverter 32. It remains as it is. The circuit 34 is inverted by the line 2 selection signal 62 (inverted!578). ) maintains latch 80 in the reset state so that line L2 Before being placed in the locked state, the scrambler/descrambler 32 is disconnected from the communication path. It operates as if it were After line L2 is placed off-hook, the reset signal is no longer supplied to latch 80, but the output of latch 80 is no longer supplied to latch 80 when the set signal is received. Stay high because you don't.

DTMF signal via line LL as indicated by DTMF detection signal 76 The reception of The output is connected to the output of multiplexer 84. However, one sit Each time circuit 90 detects a DTMF signal and for 10 seconds thereafter, The scrambler/descrambler 32 maintains the signal on 8 at a logic high state. remains separate. At the end of the 10 second period, the one-seat soft circuit 90 In order to connect the scrambler/descrambler 32 in series to the communication path, A logic low signal is provided via lexer 84. Discussion on the output of multiplexer 84 The signal is sent to the scrambler by detecting the continuous DTMF signal via the communication channel. / A one-seat circuit to prevent the descrambler 32 from being disconnected inappropriately. It is fed back to the trigger start input of 90.

Referring now to FIGS. 4A-4G, the timing of operation of various elements of system 10 is shown. The “mobile phone call” in FIG. Shows the duration of the telephone passage. This signal causes the cellular phone 12 to go off-hook. handle. The rising edge (start) indicates the start of a call, and the falling edge (hanging up the receiver) indicates the start of a call. ) indicates the end of the call.

The “Entered and Validated Security Code” in Figure 4B is a selective access code. represents the time from the time the code is entered to the time the call is terminated.

This number corresponds to the specific signal in Figure 1.2A, 2B, 3A, or 3B. isn't it.

The signal on line L2 select 1 in FIG. 40 corresponds to signal 62 in FIGS. 2A and 3B. and represents the time when line L2 is connected to hybrid 60 via relay S4. I'm watching.

The "DTMF detection" signal in FIG. 4D is the DTMF detection signal 76 in FIGS. 2A and 3B. It corresponds to This signal is used by the calling party to dial the called party. It turns on every time the button is input.

The “scrambler activation signal in Figure 4E is the scrambler activation signal in Figures 2A and 3B”. It corresponds to the signal 92 and is a signal that is “low level at startup”. This line is After the DTMF detection pulse outputs a high level signal, it remains activated for 10 seconds. Ru. If DTMF detection pulses a high level signal again before 10 seconds elapse, , the timing sequence starts over. Scrambler launch line 92 will go high again when the call is cleared.

The “scrambler input/output” signal in FIG. 4F is the result of the scrambler activation line 92. The state of the scrambler 32 as shown in FIG.

The "Called Party" signal in FIG. 4G is the period when the called party is connected to the base module 28. It represents. This signal does not correspond at all to the specific signal in the diagram0Figure 4G A rising edge indicates when the called party answers, and a falling edge indicates when the called party or indicates when the caller picks up the receiver.

As mentioned above, the scrambler/descrambler 32 processes the received DTMF signal. is activated after a time delay following . Or scrambler/descrambler 32 is activated by a request tone generated by the diverter control circuit 44. It can be activated in response to an instruction code requested by the party. This request tone occurs After that, either party may generate an instruction code consisting of a DTMF signal. . The command in which the DTMF signal received by the diverter 11Ig1 circuit 44 is held When the command code matches, the diverter control circuit 44 operates as shown by the dotted line in FIG. Then, the scrambler activation signal 92 is activated.

Although the embodiments of FIGS. 1-4 have been described with respect to a cellular telephone system, the present invention The confidentiality of communication is not limited to this, but is based on IMTS (Improved MobileTelephone 5yste), maritime wireless telephone service, etc. For example, the standard VHF- Scrambler/descrambler unit in FM maritime radio telephone transmitter/receiver 32 is connected to the speaker and microphone jack of the existing marine radio telephone. It can be done. Additionally, standard TMF signals are typically used for maritime radiotelephone services. Since it is not equipped with a standard porta-pull DTMF belt generator (Radio o 5hack Model 43 138 or equivalent) or DTM A microphone equipped with F calls the called party's phone through the system. used for.

In this application, the mobile user is connected to a radiotelephone base station or a maritime radiotelephone base station. Contact the operator and use the normal interface procedure to connect base module 2. 8 and a public telephone exchange connected via a call diverter 30. Ru. Portable DTMF generator dials the called party via base module 28 used for Once the line is set up between the mobile user and the called party, the The motive user must switch off both the encryption device on the land fixed device side and the mobile device side. Make a change. Thus, secure communications are established between the mobile user and the land-based called party. is set. This also allows the invention to prevent the called party from being equipped with equipment other than a standard telephone. (provides the ability to conduct secret communications over wireless telephone lines) . Covert radiotelephone communications between ships and the sea and between mobile stations can occur.

FIG. 5 shows another embodiment of the invention.0 communication system 500 includes first, second, and and third communication channels 502, 504 and 506. Caller 50 8 is located in a first area 510 serviced by a first local telephone company. There is. Called party 512 is in a second area serviced by a second local telephone company. 0 calling party 508 and called party 512 located at 514 are each a plurality of calling parties. For example, a company may, as part of its normal job, Must communicate by telephone with many co-workers located in the Cisco area; It may have many employees located in Washington, DC.

The first and second local telephone company equipment are interconnected via long distance telephone company equipment 516. interconnected. Equipment 516 is a wireless link such as a satellite communication line or a terrestrial microwave line. Including links.

A normal situation using only the equipment of the first and second local companies and the long distance telephone company. Under these circumstances, the confidentiality of the call between calling party 508 and called party 512 cannot be guaranteed.

Furthermore, using conventional methods and devices to provide such confidentiality; Each caller in Washington and each called party in San Francisco has a separate code. had to be connected to the decoder/decoder unit.

The embodiment of the present invention illustrated in FIG. This allows uncomplicated secret communication. 1st and equivalent to Base Mosier 28 The second base modules 520 and 522 each have a user interface as shown in FIG. Areas 510 and 5 at facilities owned or controlled by It's on 14th. Base modules 520 and 522 each have a call diverter 6 301532, bypass interface circuit 5421552, and scrubber includes an scrambler/descrambler unit 5401550. base mosier 520 are two lines established by local telephone companies serving area 510. standard telephone lines L1 and L2A. Lines L1 and L2A are assigned to them, each with an appropriate area code for the geographic region 510. Have a separate phone number assigned to you.

In the embodiment of FIG. 5, the invention provides forming a communication path between the first and second channels in response to a signal received by the channel; including first diverter means for. As realized here, the first The diverter means includes a call diverter 530. Further, the present invention provides a second and the second and third channels in response to a signal received via one of the third channels. and a second diverter means for forming a communication path between the third channel and the third channel. There is. As implemented here, the second diverter means is connected to the base module 522. including a call diverter 532 located within.

The present invention further encrypts the signal received from the second terminal, and encrypts the signal received from the second terminal. for providing a signal to the first terminal and for resolving the signal received from the first terminal. the first and second terminals for reading the decoded signal and providing the decoded signal to the second terminal; first and second encryption means, each having a first and second encryption means. It will be realized here The first and second encryption means are scrambler/descrambler units 5. 40 and 550.

Further, the present invention provides that the first terminal of the first encryption means is connected to the first channel in response to the activation signal. a second terminal of the first encryption means is connected to the second channel; a first encryption means for selectively connecting the first encryption means to the first diverter means such that As implemented herein, the first coupling means includes a bypass It includes an interface circuit 542.

The present invention further provides that the second terminal of the second encryption means is connected to the third channel in response to the activation signal. a first terminal of the second encryption means is connected to the second channel; a second encryption means for selectively connecting the second encryption means to the second diverter means; including means for coupling.

Calling party 508 and called party 512 can be accessed from public telephones located anywhere in the world. The embodiment shown in FIG. 5 may be a fixed or mobile telephone connected to a switched network. , except for the portion of the communication path provided by the long distance telephone company's equipment 516. , the confidentiality of the communication path between the calling party 508 and the called party 512 is guaranteed by other means. It is assumed that And for ease of explanation, caller 508 is a landline telephone within area 510 and called party 512 is located within geographical area 514. Assume that it is a landline phone.

Caller 508 calls the telephone number assigned to line L1 of base module 520. Initiate a call by calling. Call diverter 530 is a standard call A first activation signal is received on line L1, consisting of a signal. call diver The controller 530 puts line LL in an off-hook state in response to the ringing signal, and connects line L1 to line L1. Receive signals via. Call diverter 530 then directs caller 508 to Taking line L2A off-hook to provide dial tone Therefore, 0 calls forming a communication path between lines L1, L2A, L2B and L3 person 508 is the telephone number of line L2B of call diverter 532 within region 514 Dial. Call diverter 532 turns lines L2B and L3 off. dial tone is transmitted over line L3 by the second local telephone company. to the base module 522 via lines L2B and L2A. through the mosier 520 and is fed to line L1 and ultimately to the calling party 508. be paid.

Calling party 508 dials the telephone number of called party 512. When the called party 512 answers Then, depending on the signal received via line Ll, lines L1, L2A, L2 A communication path is established between calling party 508 and called party 512 via B and L3. . Encryptor/Decrypter such as Scrambler/Descrambler Unit 5401550 Reader circuits are connected to lines L1 and L by base modules 520 and 522, respectively. Inserted in series in the communication path between line L2A and line L2B and line L3. be done. Such insertion is in response to an access code generated by caller 508. or in response to dialing signals generated by calling party 508. Ru. Caller 508 makes the call in the normal manner, but module 520 is received via the input L1 and sent to the scrambler/descrambler unit 540. generates a signal that is more encrypted and retransmitted via line L2A. radio circuit The signal passing through the long distance telephone company's equipment 516, which may include a is encrypted for. received by module 522 via line L2B. The encrypted signal is decrypted by scrambler/descrambler unit 550. Originally, the decoding signal received from line L1 was sent to the module via line L3. 522.

In a similar manner, module 522 calls caller 512 over line L3. The received signal is encrypted by scrambler/descrambler Uni7) 510. and retransmitted to module 520 via lines L2B and L2A.

Originally, the signal received via line L3 was sent to a scrambler/descrambler unit. 540 and sent in decoded form to the calling party 508 via line L1. and then retransmitted. In this way, both the calling party 508 and the called party 512 can be scrubbed at the location. does not require a scrambler/descrambler unit, but is nevertheless Communications signals passing through long-distance telephone company 516 equipment that can be intercepted are encrypted. transmitted in encrypted form to ensure the privacy of calling party 508 and called party 512 do.

The roles of calling party 508 and called party 512 are performed by modules that perform functions contrary to those described above. The rules 520 and 522 allow for the reversal.

Frequency inversion scrambling used in the embodiments described with respect to FIGS. La/descrambler units are not very expensive and are suitable for many applications. for the communication of more sensitive information that provides an acceptable degree of confidentiality. is the frequency inversion Cellular 0ne model 19. Readily available commercially available scrambler/descrambler units such as the 05 Scrambler/Descrambler unit. From the encryption method provided by the scrambler/descrambler unit of , it is desirable to improve the level of confidentiality through more elaborate encryption methods. There are often cases. In another aspect, the invention provides associated encryption/decryption for providing signals to the device and for receiving signals from its associated encryption/decryption device. Depending on the input/output means and the activation signal, the input/output means are connected in series to the communication path. Switch between connected state and bypass state where the input/output means are disconnected from the communication path. Its input/output procedures, as implemented herein, include bypass means for The stages include interface circuits 95A-95D, and the bypass means is a multiplexer. 35A and 35B.

The present invention replaces the scrambler/descrambler unit 32 with any type may be used as a scrambler/decryption unit; Descrambler 32 is transferred to Transcript International (Transcr. ypt International) model 5C-450 encryption/decryption unit. A four-terminal device such as a block or custom high-secrecy encryption/decryption unit. This is done simply by a one-to-one replacement by the encryption/decryption unit. Ru. The devices and methods described here provide sophisticated encryption/decryption capabilities. to other users for whom such a high level of confidentiality is economically impractical. applications that require it without incurring the high cost of such sophisticated equipment. may be caused.

Various modifications and variations may be made without departing from the spirit or scope of the invention. What is accomplished in the communication system concealment device and method of the invention is within the technical field. It will be clear to those skilled in the art that the invention lies within the scope of the appended claims. Applications and modifications such as and their equivalents are within the scope of the rights.

Claims (22)

[Claims] 1. coupled to first and second communication channels, each having first and second terminations; A communication system security device used for The end is at the network exchanger, the first and second channels in response to signals received via the channels; diverter means for forming a communication path between said second end of the first and a second terminal, encrypting the signal received at the second terminal, and encrypting the signal received at the second terminal; for providing a signal received at the first terminal to the first terminal; encryption for decrypting the signal and providing the decrypted signal to the second terminal; means and In response to an activation signal, the first terminal is coupled to a second terminal of the first channel. and said second terminal is coupled to a second end of said second channel. selectively coupling encoding means to said diverter means thereby said first channel; The encrypted signal received at the second end of the channel is decrypted into the second channel. The signal received at the second end of the second channel is encrypted. a coupling means adapted for transmission via the first channel in the form of A device characterized by comprising: 2. The coupling device has a first mode in which the encryption means is isolated from the communication path. operable with a second mode in which the encryption means is serially connected to the communication path; The apparatus according to claim 1. 3. The diverter means responds to the presence of a DTMF signal on the communication path. DTMF detection means for generating a DTMF detection signal; While the DTMF signal is present on the communication path according to the DTMF detection signal, the connection is Claim 2, further comprising means for maintaining the coupling means in the first mode. equipment. 4. The maintaining means has one common terminal, one selected terminal, and a pair of selected terminals. a multiplexer circuit having a a latch circuit connected to one of the selected terminals of the multiplexer circuit; 4. The apparatus of claim 3, further comprising a timer circuit connected to the timer circuit. 5. The timer circuit operates for a predetermined period of time after the detection of the DTMF signal on the communication path. activating said multiplexer circuit to switch said coupling means to a second mode; 5. Apparatus according to claim 4, including means for. 6. The diverter means forms a communication path between the first and second channels. in response to an access code received via the first communication channel to 2. A device as claimed in claim 1, including means for: 7. The diverter means includes a pair of relays, a pair of hybrid circuits, and the diverter means. the communication path through the relay and the hybrid circuit. 2. The apparatus of claim 1, further comprising a diverter control circuit. 8. Claim 7, wherein said coupling means is connected between said hybrid circuits. The device described. 9. Said diverter means are each connected to one of said channels and are connected to one of said channels. A pair of calls each generating a ring detect signal when a signal is present on each channel. 9. The apparatus of claim 8, including an output detection circuit. 10. ．． The diverter control circuit receives signals from any of the channels. said DTMF signal such that said DTMF signal may be transmitted via the other of said channels. to form the communication path through the relay and the hybrid circuit; 10. The apparatus of claim 9, wherein the apparatus is responsive to the ring detection signal. 11. Said diverter means transmits a paging detection signal to one of said channels. a predetermined sequence of DTMF signals via the other of said channels in response to a signal. 11. Apparatus according to claim 10, including means for transmitting a signal. 12. a first and a second channel, each of said channels having a first and a second channel; , the first termination being a communication terminal located at a general network switch. A method of providing secrecy within a system, the method comprising: receiving a first activation signal via at least one of the a communication signal from a second end of the first channel in response to the first activation signal; and receive an encrypted communication signal at a second end of the first channel. a second terminal of the first channel and the second channel in response to the received communication signal; forming a communication path with a second end of the channel; a cipher in the communication path in response to the communication signal received on the first channel; selectively inserting encoding/decoding circuits, said received at a second end of said first channel to produce a decoded signal. decrypting the encrypted received signal and transmitting the decrypted signal via the second channel; and encrypting a communication signal received at a second end of said second channel. , transmitting the encrypted second channel signal via the first channel; Ru A method that includes steps. 13. The step of selectively inserting the encryption/decryption circuit includes the step of selectively inserting a DT on the communication path. MF signal is detected, and when the DTMF signal is present on the communication path, the dark The encoding/decoding circuitry remains isolated from the communication path and the DTMF signal is present. a substep of inserting the encryption/decryption circuit in series in the communication path after the 13. The method of claim 12, comprising: 14. The substep of maintaining said encryption/decryption circuitry in isolation includes said The encryption/code is removed from the communication path for a predetermined period after the code no longer exists on the communication path. The method according to claim 13, which includes a substep of maintaining the decoding circuit in isolation. Law. 15. communications used to couple to the first, second, and third communication channels; A system security device, in response to a signal received via one of the first and second channels; a first diverter for forming a communication path between the first and second channels; means and in response to a signal received via one of said second and third channels; a second diverter for forming a communication path between the second and third channels; means and each encrypting a signal received from said second terminal, and transmitting said encrypted signal. a signal for providing to and receiving from the first terminal; a first and a second terminal for decoding the decoded signal and providing the decoded signal to the second terminal. first and second encryption means having two terminals; and in response to an activation signal, said first a first terminal of an encryption means is connected to the first channel, and a first terminal of the encryption means is connected to the first channel; said first encryption such that a second terminal of said means is connected to said second channel; first coupling means for selectively connecting means to said first diverter means; In response to an activation signal, a second terminal of said second encryption means is connected to said third channel. connected, and a first terminal of said second encryption means is connected to said second channel. selectively connecting said second encryption means to said second diverter means so as to a second coupling means for connecting the first channel to the first channel by the apparatus; The signal received from the channel is transmitted encrypted via said second channel. is retransmitted in a decrypted state via the third channel, and is transmitted by the device. The signal received from said third channel is encrypted via said second channel. transmitted in a decrypted state and retransmitted in a decrypted state via the first channel. equipment. 16. Confidentiality in communication systems with primary, primary, and tertiary channels A method for bringing about receiving a first activation signal via one of the first and third channels; In response to the first activation signal, receiving a communication signal from the first channel, said first, second, and third in response to a communication signal received over a channel. A communication path is formed between the channels, and communication signals received via the channels are connected to each other. between the first and second channels and between the second and third channels; selectively inserting an encryption/decryption circuit into the communication path of the said first channel to form an encrypted first channel communication signal. encrypting the communication signal received via the second channel; retransmitting the encoded communication signal on the first channel and receiving it via the second channel; decrypts the encrypted communication signal of the first channel, and decodes the encrypted communication signal of the third channel. The decrypted communication signal of the first channel is retransmitted through the encrypted received via said third channel to form a third channel signal. encrypting a communication signal and transmitting the encrypted third channel via the second channel; retransmits the encrypted channel signal received via the second channel. decoding a communication signal on a third channel; and decoding the decoded communication signal via the first channel. The method includes the step of retransmitting the communication signal through the third channel. 17. each having a first and a second termination, the first termination being a network used to couple the first and second communication channels at the switch A security device for a communication system, comprising: a security device for a communication system; forming a communication path between the second ends of the first and second channels according to the diverter means for transmitting the signal to the relevant encryption/decryption equipment and input/output means for receiving signals from the related encryption/decryption device; The input/output means is circuit-connected in series to the communication path in response to an activation signal. A connected state and a bypass state in which the input/output means is isolated from the communication path. and bypass means for switching between. 18. used to couple to the first, second, and third communication channels; The first and third channels are each connected to a first channel at a common network switch. A communications system that has one termination and a second termination at a location other than a general network switch. one of the first and second channels; a second end of said first channel and a second end of said first channel in response to a signal received through said first channel; a first diverter means for forming a communication path between the two channels; in response to a signal received via one of the second and third channels. forming a communication path between a second end of the channel of No. 3 and the second channel; a second diverter means for encrypting a signal received from said second terminal; for providing an encrypted signal to the first terminal; and decoding the signal received from the second terminal and providing the decoded signal to the second terminal. first and second encryption means each comprising first and second terminals for In response to an activation signal, a first terminal of said first encryption means is activated to activate said first channel. a second terminal, a second terminal of said first encryption means being connected to said second channel; selecting said first encryption means to be connected to said first diverter means; a first coupling means for selectively connecting; and in response to an activation signal, said second encryption means; a second terminal of the means is connected to a second end of the third channel, and a second terminal of the means is connected to a second end of the third channel; said second encoding means such that a first terminal of said encoding means is connected to said second channel; second coupling means for selectively connecting encoding means to said second diverter means; , whereby the signal received by the device from the first channel is transmitted in encrypted form via the second channel; is retransmitted in a decrypted state via the third channel, and The signal received from the A device for retransmitting in decrypted form via a first channel. 19. a first, a second, and a third channel; the first and third channels; The network has a first termination at a public network switch and a second termination at a location other than the public network switch. A method for providing confidentiality within a communication system having a termination, the method comprising: receiving a first activation signal via one of the first and third channels; In response to the first activation signal, the communication signal from the first channel is received, and the first channel a second terminal of said third channel in response to a communication signal received through the channel; and the second channel, the communication path being received via the channel. between the second end of the second channel and the third channel in response to a communication signal that and a second end of the second channel and the third channel. selectively inserting an encoding/decoding circuit to form an encrypted third channel signal. a communication signal received via the third channel for the purpose of encrypting the communication signal received via the third channel; retransmitting the encrypted third channel communication signal through the second decoding the encrypted third channel communication signal received via the third channel; and read the decrypted third channel communication signal via the first channel. A method including the step of retransmitting. 20. first and second communication channels each having first and second terminations; a communication system security device used for The end is at the rope changer, the first and second channels in response to signals received via the channels; diverter means for forming a communication path between said diverter means; a first orifice for connecting to the second ends of the first and second channels, respectively; and a diverter means including a first and a second connecting means, and a first and a second terminal; encrypting the signal received at the second terminal; and transmitting the encrypted signal to the first terminal. decoding a signal for supplying to a terminal and received at said first terminal; encryption means for providing a decrypted signal to the second terminal; In response to an activation signal, the first terminal is coupled to a second terminal of the first channel. and said second terminal is coupled to a second end of said second channel. selectively coupling encoding means to said diverter means thereby said first channel; The encrypted signal received at the second end of the channel is decrypted to the second channel. The signal received at the second end of the second channel is encrypted. a coupling means adapted to be transmitted over the first channel in the form of A device characterized by comprising: 21. used to couple to the telephone lines of the first and second switched connected networks A security device for a telecommunications system, which protects the telephone line of said switched network. in response to a signal received via at least one of the first and second diverter means for forming a communication path between telephone wires connected together, comprising: , said diverter means to said first and second switched network telephone lines, respectively. , diverter means including first and second connection means for connecting; having first and second terminals, encrypting a signal received at said second terminal; for providing an encrypted signal to the first terminal; and the first terminal. for decoding a signal received at the second terminal and providing the decoded signal to the second terminal. an encryption means for In response to an activation signal, the first terminal is coupled to a second terminal of the first channel. and the second terminal is coupled to a second end of the second channel. Encrypting means is selectively coupled to said diverter means, thereby encrypting said first channel. an encrypted signal received at a second end of the channel via said second channel. a signal transmitted in decrypted form and received at a second end of said second channel; is transmitted over said first channel in encrypted form. means and A device characterized by comprising: 22. In a communication system having first and second switched connected telephone lines. means for providing confidentiality when the first and second exchange connections are connected; receiving a first activation signal via at least one of the telephone lines of the network; In response to the first activation signal, communication from the telephone line of the first switched network is activated. a telephone line of the first switched connected network; in response to a communication signal received via a telephone line of said first switched connected network; forming a communication path between the telephone line and the second exchange-connected telephone line; responsive to the communication signal received via the telephone line of the first switched connected network; selectively inserting an encryption/decryption circuit into the communication path to produce a decrypted signal. the encrypted data received over the telephone line of the first switched connected network for decoding the received signal and transmitting the decoded signal via the telephone line of the second switched connected network; a communication signal received via a second end of the second channel; and transmitting the encrypted first 2 exchanges transmit signals on connected network telephone lines A method that includes steps.