MXPA99007099A - Communications system for remote control systems - Google Patents

Abstract

A communications system for transmitting and receiving remote control messages in an electronic remote control system. The present communications system uses a remote control message protocol which is particularly suitable for transmitting RF remote control messages with IR remote control messages in a time multiplexed fashion, wherein the RF remote control messages are transmitted during the pause intervals between IR remote control message transmission intervals. The present remote control message protocol (80) includes a start sequence (82), comprising a MARK pulse and a SPACE of about equal duration, followed by a plurality of data fields. Each data field ends with an End of Field marker (85) and the remote control message ends with an End of Message marker (87). The plurality of data fields comprises an addressing data field (89) for specifying the destination device, a security code data field (89) for allowing a specific remote control transmitter to control a specific destination device, a status field (88) for specifying various status codes associated with the remote control message, a keycode field (90) for carrying the remote control message payload, and a checksum field (92) for verifying the transmission integrity of the remote control message. A remote control message based on the present message protocol may be expanded to include additional data fields and to expand pre-existing data fields.

Description

COMMUNICATIONS SYSTEM FOR REMOTE CONTROL SYSTEMS BACKGROUND OF THE INVENTION The present invention relates to a communication system, and more particularly, to a communication system for transmitting and receiving remote control messages to electronic control devices. A variety of remote control systems that transmit and receive remote control messages to control various electronic devices is known. Such systems commonly include a remote control device comprising an input device, such as a keyboard, to allow user input, coupled to a controller, which in turn is coupled to a signal transmitter. In response to a user input, the controller generates an appropriate remote control message using search tables, and the like, from the memory and causes a signal transmitter to transmit the remote control message. The signal transmitter may be designed to transmit the remote control message in a number of different ways, including, but not limited to, an infrared signal and a radio frequency signal. A commonly used method of sending a remote control message is to transmit the message in the form of an infrared signal.

Remote control devices that transmit infrared signals are well known and are commonly used with home electronic devices. The message format of the infrared signal is determined by the manufacturer for each model and many infrared message formats are known and used. Each format specifies a series of message characteristics, including, but not limited to, duration, transmission, and message pause intervals and data types conveyed in the remote control message. However, there are several disadvantages associated with the use of infrared signals to control an electronic device. First, the infrared signal is directional and as such requires the user to point the remote control device towards the destination device for proper transmission operation. Also, the infrared signal can have a relatively short range and is easily blocked by objects such as walls, floors, ceilings and the like, so a remote control device should generally be used in the same room in which the device is placed. destination. Also, many existing infrared signal message formats do not have sufficient data transport capacity to transmit the different types of remote control data required to control many modern electronic devices. For example, in addition to the conventional remote control messages associated with home electronic devices, such as on, off, channel up, channel down, etc. , many modern electronic devices, such as satellite receivers, may require that the remote control device send other forms of data, such as ASCI I character data. Many infrared signal message formats are not designed to handle these additional forms of data and / or simply do not include sufficient capacity to carry the data. Another method of sending a remote control message is to transmit the message in the form of a radio frequency signal. Radio frequency signals are generally non-directional and have a greater range than infrared signals. Radio frequency signals can also be transmitted through objects such as walls, and the like, so that the user can use the remote control device to control a device in another room. This extended range and ability to transmit messages through objects is beneficial in situations where a central device, such as a box that is placed on top of an appliance or a satellite receiver, provides input to a plurality of devices placed in different rooms in a building. Also, the radio frequency signal message formats generally have wider bandwidths and then have higher data transport capacity, than the existing infrared signal formats. As such, it is desirable to be able to use radio frequency signals to control modern electronic devices. However, devices and methods that use infrared signals are still popular and widely used. To maintain backward compatibility, that is, to allow a remote control device to control existing devices using infrared signals, a remote control device must also be capable of transmitting infrared signals. Therefore, it is desirable to have an apparatus and method for easily and efficiently transmitting some combination of radio frequency and infrared signals to take advantage of the characteristics of the two forms of signal transmission. However, the infrared signal message formats, or protocols, are not entirely suitable for transmitting remote control messages in the form of radio frequency. Since radio frequency signals have a longer range and transmit through objects better than infrared signals, a radio frequency signal message format must include a method of avoiding the interference of nearby radio frequency signal transmitters. Also the existing infrared signal message formats do not allow a remote control device to send different types of data, such as ASCI I data, in addition to the standard commands of infrared signals. Additionally, the existing infrared signal message formats do not fully exploit the increased bandwidth and expansion capacity associated with radio frequency signals. The limited use of available bandwidth and limited expansion capacity reduces the ability to efficiently transmit and receive additional data, as well as more complex data, thus limiting the ability to add new types of remote control devices to an existing system and incorporate new functions to existing remote control devices. BRIEF DESCRIPTION OF THE I NVENCTION PC Therefore, what is needed is a communications system for use in a remote control system that provides greater capacity for expansion and data transport. In particular, what is needed is a communications system that uses a message protocol that provides the ability to efficiently transmit and receive a greater amount of data, as well as different types of data, compared to existing control message protocols. remote. Additionally, what is required is a message protocol that can be expanded to carry an additional amount of data and / or more types of data, being forward and backwards compatible with existing and future receivers / decoders. The present invention includes a communications system that uses a message protocol that provides for the transmission and reception of complex data, as well as different types of data, such as ASC II data, and allows message expansion as required, in a format efficient. The present communication system and message protocol are suitable for transmitting and receiving remote control messages in the form of a radio frequency signal, and especially suitable for transmitting and receiving a radio frequency signal in combination with an infrared signal by multiplexing in time of the two signals. In accordance with one aspect of the present invention, a remote control apparatus is provided, comprising an input device for receiving remote control messages from a user, a signal transmitter, and a controller operatively coupled to the input device and the signal transmitter, the controller generates a remote control message and causes the signal transmitter to transmit the remote control message in response to user input, the remote control message comprises a plurality of data fields, each of the data fields ends with a field marker end, the plurality of data fields comprises a state field having signal transmission information including a bit of key code type, and a key code field having one of first and second data according to a bit state of key code type. In accordance with another aspect of the present invention, a remote control system is provided, comprising an input device for receiving remote control messages from a user, a transmitter for the infrared signal, a transmitter for the radio frequency signal and a controller operatively coupled to the input device, the transmitter of the infrared signal and the transmitter of the radio frequency signal, the controller generates an infrared remote control message and a radio frequency remote control message and causes the transmitter of the infrared signal and the remote radio frequency transmitter transmits infrared and radio frequency remote control messages, respectively in a time multiplexed manner in response to user input, the radio frequency remote control message comprises a plurality of data fields, each of the data fields ends with a field marker end, the plurality of data fields comprises a state field having signal transmission information including a key code type bit, and a key code field having one of first and second data in accordance with a bit state of key code type. In accordance with another aspect of the present invention, a remote control apparatus is provided comprising an input device for receiving remote control messages from a user, a signal transmitter, and a controller operatively coupled to the input device and the transmitter. of signals, the controller generates a remote control message and causes the signal transmitter to transmit the remote control message in response to user input, the remote control message comprises a start sequence comprising a pulse and pause period having approximately the same duration, a preamble field having data to address a destination device, a security code field having an identifier associated with said signal transmitter, a status field having transmission status information of signals, a key code field that has either first or second data according to a bi t of key code type in the status field, a sum check field to verify the integrity of the transmission of the remote control message and a message marker end. In accordance with another aspect of the present invention, there is provided a remote control apparatus comprising a signal receiver adapted to receive a remote control message, a controller operatively coupled to the signal receiver, the controller adapted to decode and process the remote control. remote control message, the remote control message comprises a plurality of data fields, each of the data fields ends with a field marker end, the plurality of data fields comprises a status field having transmission information of signals including a key code type bit, and a key code field having one of first and second data in accordance with a state of the key code type bit. In accordance with another aspect of the present invention, a method of transmitting a remote control message is provided, comprising the steps of: receiving a user input; generating a remote control message corresponding to the user's input, the remote control message comprises a start sequence followed by a plurality of data fields and a message marker end, each of the data fields ends with a end of field marker, the plurality of data fields comprises a preamble field having data to address a destination device, a security code field having an identifier associated with the remote control apparatus, a status field having transmission status information about the remote control message, a key code field having data associated with the user input and a sum check field to verify the transmission integrity of the remote control message; and applying the remote control message to a signal transmission circuit. BRIEF DESCRIPTION OF THE DIAMETERS The invention will be described with reference to the accompanying drawings, in which: Figure 1 is a block diagram showing the elements of a remote control device suitable for use in the present communications system; Figure 2 is a block diagram illustrating the basic elements of a transmitter of the appropriate radio frequency signal; Figure 3 is a block diagram illustrating the basic elements of a suitable radio frequency receiver; Figure 4 is an illustration of a transmission sequence of infrared and radio frequency remote control messages, wherein the infrared and radio frequency messages are transmitted in a multiplexed manner in time; Figure 5 is an illustration of the data fields in a remote control message protocol of the present communication system; Figure 6 is an illustration of the waveform of the MARCA and ESPAC IO portions of the remote control message protocol; Figure 7 is an illustration of a waveform of a symbol in the remote control message protocol; Figure 8 is an illustration of a waveform of a remote control message using main zero suppression; Figure 9 is an illustration of adding a new data field in the remote control message protocol; Figure 10 is an illustration of expanding a preexisting field in the remote control message protocol; Figure 11, is an illustration of using main zero suppression when expanding a preexisting field in the remote control message protocol; Figure 12 is a block diagram illustrating the basic elements of a signal receiver / decoder suitable for use in the present communication system; and Figure 13 is a flow diagram illustrating the steps of an altting method. DETAILED DESCRIPTION OF THE USED DETAILED DESCRIPTION OF THE PRIOR ART With reference to Figure 1, a simplified block diagram of the remote control 10 suitable for use with the present communication system is shown. The remote control 10 can take many forms, such as a standalone unit or a portion of a larger communication device, and be adapted for use with a variety of electronic devices. For example, devices incorporating the elements and signaling characteristics of the remote control 10 include, but are not limited to, a wireless keyboard, wireless signaling devices and portable remote control devices for controlling consumer electronic devices. It should be understood that the present remote control can be used with any system adapted to transmit, receive or process remote control messages in response to a user input. Generally, the user input is received through the input device 20, which includes several control buttons, device selection buttons, numeric buttons and the like. It should be understood that the input device 20 can include any device where the user can provide an input to the remote control 10 and includes, but not limited to, a matrix of keyboard, mouse, trackball, joystick and other types of pointing devices. The input device 20 is operatively coupled to the controller 14, which controls the overall operation of the remote control 10. The controller 14 receives input from the user, and generates and produces the transmission of an appropriate remote control message. The controller 14 may comprise any of a plurality of conventionally known devices, which may be in the form of an integrated circuit, which are capable of performing control functions. Suitable controllers include, but are not limited to, ST 7291 and ST 7225 manufactured by SGS Thomson Microelectronics. The timing of the controller 14 is controlled by the crystal oscillator 18. Upon receipt of a user input from the input device 20, the controller 14 uses the designated reference code, or other identification information to search for the desired information from the user tables. search of product code stored in memory 22 to identify and generate a remote control message having the correct signal structure. Characteristics of the signal structure include, but are not limited to, the appropriate carrier frequency, pulse width, pulse modulation, and general signal timing information. The memory 22 may comprise random access memory and / or read-only memory and be positioned either internally or externally to a housing associated with the remote control 10. The controller 14 applies the appropriate remote control signal to the infrared transmitter 16 and / or radio frequency transmitter 17 to send the signal to the destination device. The controller 14 also controls the display 12, which may include, for example, indicator light emitting diodes, to indicate that a remote control message has been transmitted. When the remote control message is transmitted, an infrared receiver and / or a radio frequency receiver associated with the destination device detects the remote control message and provides the message to the processor of the destination device for decoding and processing. Figures 2 and 3 show the radio frequency transmitter 40 and the radio frequency receiver 50, respectively, suitable for use in sending and receiving radio frequency message in the present communication system. As shown in Figure 2, the radio frequency transmitter 40 comprises the bipolar oscillator 46 with a SIERRA resonator of a frequency stabilization port coupled to the mixer 44, which activates a linearly polarized circuit antenna 48, which is commonly placed in the housing of the remote control 10. When the user provides an input, for example by pressing a key, the controller 14 generates a modulation signal that is used to turn the oscillator 46 on and off to set the amplitude shift of the carrier. Generally, it is desirable that the transmitter 40 include minimal parts due to the limited space in the housing of the remote control 10. A suitable radio frequency receiver 50 is shown in Figure 3. The radio frequency receiver 50 will commonly be placed on or connected to the host of the target device. The receiver is capacitively coupled to the antenna 52, which can conveniently be a line cable that acts as a receiving antenna, in which case the radio frequency signal enters through a connector placed in the housing around the receiver. radio frequency 50. The signal is amplified by the low noise amplifier 54, which reduces the noise level of the entire system while increasing the sensitivity of the receiver. The output of the amplifier 54 passes through the image filter 56 which provides rejection of the image frequency. The signal is then converted via mixer 58 and local oscillator 60 to an intermediate frequency (IF) of 10.7 MHz. The intermediate frequency signal is passed through filter 62 and amplified by a chain of high gain logarithmic amplifiers 64. which convert the signal into an output current. The output current is converted to a voltage, it is passed to a noise level minima adapter 66, and is filtered by low pass through the data filter 68 before being sent to the processor of the target device for decoding and processing. Any of a number of conventionally known infrared transmitter and receiver configurations can be used to send and receive infrared remote control messages in the present invention. Generally, an infrared transmitter includes a light emitting diode coupled to a light emitting diode activating circuit, which is controlled by the controller 14. In response to a user input, the controller 14 generates an infrared remote control signal of according to the search table in memory 22 and applies the infrared remote control signal to the light emitting diode activating circuit. The light emitting diode activating circuit activates the light emitting diode to project an infrared signal towards the controlled device. An infrared light sensor in the infrared receiver detects the infrared signal and provides the signal to a processor in the target device for decoding and processing. Suitable configurations of infrared and radio frequency transmitter and receiver include, but are not limited to, those found in the DSS DS5450RB system manufactured by Thomson Consumer Electronics Inc., of Indianapolis, Indiana. The remote control 10 transmits the infrared signal, the radio frequency signal or any combination thereof to control an electronic device in response to user input. Conveniently, for transmitting a radio frequency signal and an infrared signal for each user input, wherein each signal is generated according to a respective message protocol, the remote control 10 can transmit the two messages in a time multiplexed manner. In particular, the radio frequency and infrared signals can be transmitted alternately with the radio frequency signal transmitted during the pause interval of the infrared signal as shown in Figure 4. In the signal transmission sequence 70, the Infrared signals are transmitted during the intervals 74 and 78 while the radio frequency signals are transmitted during the pause intervals 72 and 76. The transmission sequence described above is particularly suitable for use with infrared signal protocols since said protocols generally require Repeated intervals of infrared signal transmission interrupted by pause intervals. The radio frequency signals can easily be transmitted during the pause intervals without affecting the transmissions of the infrared signals. Commonly, the pause interval between infrared transmissions lasts between 2-10 mS. A sequence of this type can be implemented using relatively inexpensive controllers. An apparatus and method for transmitting infrared and radio frequency messages in this manner is described in the copending patent application of the United States of America, entitled "Method and Remote Control Apparatus" which is assigned to the assignee hereof. request . The present communication system uses a remote control message protocol that is particularly suitable for transmitting radio frequency remote control messages in the multiplexed manner described above. The structure of the data field and the associated timing of the present remote control message protocol allows a radio frequency message using the present remote control message protocol to be easily transmitted in the pause intervals as described above. However, it should be understood that the present remote control message protocol can be used with any means of signal transmission, such as infrared transmissions., and can be used by any method of message transmission, and is not limited to its use in multiplexed transmission schemes. The structure of the present remote control message protocol is shown in Figure 5. The remote control message 80 comprises a start sequence comprising the MARK / SPACE combination 82 followed by a plurality of data fields. The illustrated remote control message comprises five data fields. However, as described further below, the number of data fields may be increased if the remote control message needs to be expanded to obtain greater functionality. Each field ends with an End of Field marker (EOF) 85. The use of an End of Field marker allows the size of a particular field to be expanded without changing the existing data fields in the message protocol. The end of the message is marked by the end of message marker (EOM) 87. The use of a Message End marker allows increasing the number of fields transmitted in the remote control message without changing the existing data fields in the protocol . It can be seen that the use of the End of Field marker 85 and the End of Message marker 87 allows the present message protocol to handle a greater number of devices and functions without altering the existing radio frequency systems in the field. The format of the BRAND / SPACE combination 82 and the data within the data fields are described below. The MA RCA / SPACE 82 combination, as shown in Figure 6, signals the start of a new remote control message and is used at the destination receiver to distinguish the beginning of the message from the pulses produced by the background noise. The BRAND pulse 102 is designed to be wider than the synchronization pulses that make up the rest of the remote control message. The special length of the BRAND pulse 102 and the next pause period, namely SPACE 104 allows the receiver / decoder to recognize the beginning of the remote control message of the background noise and the partial messages of other remote control devices. The appropriate timing for the BRAND 102 pulse and ESPAC IO 104 are shown in Table 1 below (units in uS): TABLE 1 Minimum Typical Maximum MARK pulse width 90 100 1 10 SPACE signal time 90 100 1 10 Following the MARK and ESPAC IO, the signal transmitter transmits a plurality of data fields. The data in each data field comprises a plurality of symbols that include: "1", "0P and EOF.The remote control message is terminated with the EOM symbol.Each of the symbols comprises a waveform. which comprises a synchronization pulse and a pause space, and as shown in Figure 7, the waveform 105 is defined by synchronous pulse width 106 and the total symbol time 108. The appropriate values for the width of sync pulse 106 and total symbol time 108 for each symbol is shown in Table 2 below (units in uS, except for EOM that is in mS): TABLE 2 Minimum Typical Maximum Synchronization pulse width 45 50 55 ( all symbols) Total symbol time "1" 1 60 1 75 1 90 Total symbol time "0" 21 0 225 240 Total symbol time EOF 260 275 290 Total symbol time EOM .30 65 infi nite Each data field It contains 8 bits of data and is transmitted in the order of the first bit. s significant and last the most significant bit. The data fields also have suppression of main zero to reduce the data transmission time, where any of the most significant bits not transmitted for a particular byte when the EOF signal is received is assumed to be "0P The structure and order of Transmission, from left to right, of a sample data field is shown below: BIT0 BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 B IT7 EOF If the field has at least one more significant bit that is zero (data byte less than 80hex, bit 7 or more clear), then these bits would not be transmitted and a End of Field marker is transmitted after the bit of the final series. An End of Message marker would replace the End of Field marker for the last field, indicating to the receiver that no more fields are coming and that message processing can begin. An example of a remote control message demonstrating the use of principal zero suppression and illustrates the use of the different symbols described above, is shown in Figure 8. In Figure 8, remote control message 1 10 comprises the sequence start 1 12, followed by data fields 1 13 - 1 16 and end of message marker 1 17. Data fields 1 13 - 1 16 transmit "OD", "OOP" OE "and" 3B "respectively. Byte "00" is represented with only one EOF symbol, with all the main zero bits suppressed Also, the End of Message marker 1 17 replaces the End of Field marker for the last field 1 16. The data associated with each of the data fields shown in Figure 5 are described below.The preamble field comprises an identification code associated with the destination device and is used to address the destination device.The code data in the field of preamble may correspond to the preamble codes used in the pre-existing remote control message protocol, for example the Thomson Consumer Electronics, Inc. Specification 15206770. All valid radio frequency device preamble fields must correspond to the preambles assigned by the manufacturer's specifications. Conveniently, the preamble of future compatible radio frequency products can be designed to be addressable using the existing infrared preamble codes. The privacy code field comprises a 3-digit number in the range of 000-255 which is programmed into the remote control 10 by the user and uniquely identifies the transmission source of the remote control message. The privacy code allows the receiver to respond only to the appropriate remote control device and messages that carry incorrect privacy codes are ignored. The receiver for the target device includes its own user interface to determine which privacy code to accept. The privacy code function is particularly convenient in applications for transmitting radio frequency signals to prevent radio frequency transmitters from affecting the target device and the present remote control device affects nearby radio frequency receivers. As such, the privacy code function is particularly beneficial in densely populated areas in which many other radio frequency remote control devices may be operating. The preamble and security code fields are first transmitted to allow the rejection of the message by the destination device first in order to improve the operation of the system. The privacy code function also provides an additional addressing capability if several recipients within the range use the same preamble code. For example, if a user wants to control 4 Digital Satellite System ("DSS") receivers where the DSS remote control that includes keys for "DSS 1" and "DSS 2", a pair of DSS receivers may be associated with the "DSS 1" key and configured to respond to a first and second privacy code, respectively, and another pair of DSS receivers may be associated with the "DSS 2" key and configured to respond to the first and second privacy codes, respectively. Any conventionally known method can be used to program remote control devices to assign security codes, for example, the user can program the remote control device by pressing a key of the appropriate device., for example, Television, Video Cassette Recorder or DSS, and then insert a security code, for example, three-digit code. Alternatively, the user can be guided through the programming sequence by means of an appropriate user interface, for example, a menu in a screen display. The status field provides status information about the transmission of the remote control message and includes the following indicators: Bit 7 - Bit 2: not currently used Bit 1: Key Code Type Bit 0: Key Pressure Status The bit key code type (bit 1) indicates that the data conveyed in the key code field is one of the two types of data depending on the state of bit 1, for example, a key code data of Thomson Consumer Electronic ("TCE") or an ASCI I character data byte of an alternative device, such as a keyboard, mouse, tracking sphere, etc. The key pressure status bit (bit 0) alternates with each new key pressure on the remote control 10. The key code type bit, together with the timing of message separation helps the receiver determine whether a message is a repeated message of a key pressure or the result of another key pressure on the remote control device 10. As described further below, the key code type bit is used in an alteration method to distinguish new pressures of remote control keys 10 of the previous ones thus preventing the receiver from performing multiple responses to a single key pressure on the remote control device 10. Bit 7 to bit 2 are reserved for future expansion and must produce a value of omission "0" to take advantage of the main zero suppression function of the present remote control message protocol. The key code data field includes the data associated with the user input, such as a command or character data associated with a particular key. The data transported in this field can comprise data of any suitable format to transmit the user's input. In the present remote control message protocol the data conveyed in this field comprises either an 8-bit standard key code associated with a pre-existing infrared protocol, such as the Thomson Consumer Electronics, Inc. Specification 15206770, or one byte of ASCI I character data depending on the status of the key code type bit in the status field. The sums check byte field is used to verify the precise receipt of the remote control message for all fields in the remote control message up to, but not including, the sum check field. All fields before the sum check field are added using 8-bit addition and the result is transmitted in the sum check field. The present remote control message protocol can be modified to add additional data to the message while maintaining forward and backward compatibility with future remote control receivers and transmitters. Modification of the present remote control message protocol may be necessary, for example, to accommodate additional electronic devices with additional functions for a particular electronic device. Modification of the present remote control message protocol can take many forms, including, but not limited to, adding a new data field, expanding a field beyond 8 bits, and adding additional status bits. The modification of the present remote control message protocol to add a new data field is illustrated in Figure 9. A new data field may be required due, for example, to the addition of a new function in the remote control device 10 or on the target device. The new field 152 inserts between the existing data fields 151 and the sum check field 153, that always the last field of the message. The additional data field increases the overall length of the remote control message, but does not affect the existing data fields 151 of the remote control message. In this way, the present remote control message protocol can be easily modified to add additional functions and still be able to control the target devices that are based on previous versions of the protocol. Modification of the present remote control message protocol to expand a field size is illustrated in Figure 10. The expansion of a field may be necessary to accommodate, inter alia, additional types of remote control devices and increased functionality of the devices of existing remote control. If a field requires an increase in size beyond 8 bits, a new field is added and placed immediately before the original field that required the expansion. In the example shown in Figure 10, the expansion of the key code field is performed by adding a high byte field of key code 163 between the state field 161, and the key code field 162 and the verification field of sum 164. If the expansion of the key code requires an increase of 8 to 10 bits, then the bits will be transmitted in the order shown in Figure 1 1. In this case, bits 9 and 10 of the high code key byte would be located in bit 0 and 1 of high byte field 171, respectively, while the remaining bits are transmitted in field 172. Field 172 would always be transmitted , even if the additional bits are all "0" and only the EOF symbol is transmitted. This allows the decoder in the destination device to distinguish which version of the protocol is being transmitted. With respect to adding additional state information, the additional status bits are assigned starting from the first available least significant bit not used to reduce the transmission time. If all 8 bits of the status field are assigned, an additional field is added as described above, immediately before the existing status field.

A receiver / decoder may be programmed to determine the version of the received remote control message by examining the number of fields and / or the number of bits in a particular data field. By determining the version of the remote control message in this manner, the current receivers / decoders can maintain forward compatibility, that is, process a future version of the present remote control message protocol, and future receivers / decoders can maintain the backward compatibility, that is, processing past versions of the present remote control message protocol.

Forward compatibility is maintained by designing the receiver / decoder to process additional fields of future protocol versions only to calculate the checksum and assume that the last field is the checksum byte. For example, since the original version of the present remote control message protocol contains 5 fields, the receivers / decoders designed to process only this remote control message protocol version would use only the first 4 fields and would not consider the remaining fields, but which would add the entire field in the received remote control message, including those of the first four, for the checksum and compare the result to the sum check field. Future transmitters using the present remote control protocol should be designed to send the sum check field to the last one so that a previous receiver / decoder version correctly processed the basic message. Backward compatibility is maintained by designing the receiver / decoder to always verify previous versions of the remote control message protocol by examining the number of received data fields and processing the remote control message accordingly. If a bit of data is added to the original state field, then the polarity of the new indicator should be oriented so that a previous remote version, that is, one that does not transmit the bit and therefore by default designates it as " 0"does not produce an undesirable action on the receiver.

As indicated above, the present remote control message protocol is particularly suitable for transmission in the form of a radio frequency signal, especially during the pause intervals of infrared remote control signal transmission intervals. The waveforms defined above and their associated timing ensure that radio frequency messages can be transmitted during said periods without adversely affecting the infrared transmission. The present message protocol also allows for transmitting additional data types and allows expansion to accommodate greater functionality, as well as allowing forward and backward compatibility. Additionally, the present message protocol provides security codes to prevent unwanted transfer of other radio frequency remote controls. A suitable receiver for detecting, decoding and processing the aforementioned radio frequency and infrared signals will be described below. As shown in Figure 12, the suitable receiver 200 comprises the controller 202 which receives the radio frequency and infrared signals through the receiver of the infrared signal 208 and a receiver of the radio frequency signal 210. The controller 202 decodes and processes the received remote control signal and sends control signals to the device mechanism 206 to perform the operation specified by the received remote control signal. The device mechanism 206 comprises any of a plurality of components included in an electronic device that can be controlled by the remote control signal. Such components include, but are not limited to, radio frequency tuners, conveyor of video recorder tape, DSS transport decoder and physical equipment of deflection of television tube. Controller 202 is also connected to memory 214 and screen 204, which may include, for example, a front panel indicator to display the status of the receiver, a series of indicator lights, an alphanumeric screen or a display screen. The timing of the controller 202 is controlled by the oscillator 212. When an infrared signal is directed to the receiver 200, the receiver of the infrared signal 208 detects and provides the infrared signal to the controller 202. The controller 202 decodes and processes the infrared signal received with based on the appropriate infrared format specification. Likewise, the controller 202 receives radio frequency signals via the receiver of the radio frequency signal 210 and decodes and processes the received radio frequency signal, based on the appropriate radio frequency format specification. The elements of the receiver 200 and its operation are generally known in the art. The receiver 200 may be designed to perform the functions of reception, decoding and processing in a number of predetermined modes or modes selected by a user. First, the controller 202 may be programmed to decode and process the radio frequency and infrared signals in the order in which the signals are received. In this case, the controller 202 sends the necessary control signals to the mechanism of the receiver 206 as the respective remote control signals are detected. Second, the receiver 200 may be configured to decode and process the incoming signals according to a predetermined priority or a priority selected by a user. For example, if the infrared signals are selected as having higher priority, the controller 202 may be programmed to ignore the radio frequency signals, or to store the radio frequency signals for processing at a later time if the infrared signals are present. Also, a particular signal can be given higher priority in the form of interrupting the decoding process to service the higher priority signal. For example, if the infrared signals are selected as being of higher priority, the controller 202 may be programmed to temporarily stop the processing of radio frequency signals as soon as an infrared signal is detected. Priority selections can be made using any conventionally known method, including, but not limited to, using a screen display menu. The receiver 200 may also be configured to respond to a single type of signal, or to a series of signals, and to ignore other types of signals. For example, if receiver 200 is programmed to be used with infrared signals only, controller 202 will ignore all radio frequency signals. Again, receiver 200 may be selected to respond to or ignore particular signals using conventional user interface methods. Although Figure 12 shows the receiver of the infrared signal 208 and the receiver of the radio frequency signal 210, it is to be understood that the receiver configurations described above can be implemented in a receiver having a plurality of signal receiver types and any number of signal receivers. Due to the intervals of transmission of repeated radio frequency signals associated with each user input and the possibility of interference corrupting the individual messages when the present remote control message protocol is transmitted in the form of radio frequency, a receiver / decoder of The radio frequency associated with the target device must contain a process to determine if a received message should be carried out or if it should be ignored. A Appropriate processing method is described below. Such a method can be implemented in the radio frequency receiver / decoder by programming a destination device driver as is known in the art. The present method allows the radio frequency receiver / decoder to distinguish new key pressures of the remote control 10 from the previous ones. This is necessary to prevent the radio frequency receiver / decoder from making multiple responses to unique key presses of the remote control.

The two basic inputs of the present method are the timing from the last operation and the state of a key pressure status bit in the message protocol status field described above. The timing of the last operation is measured by two separate timers, a short timer and a long timer. Timers can be implemented in computers or computer programs, for example, as part of the controller's integrated circuit. The short timer determines whether repeated messages from a remote key press have ended or a long timer is used to determine whether a key pressure status bit should be verified. The key pressure status bit is a status indicator that alternates with each key press. The appropriate timer values for the short timer are 4-6 mS and for the long timer they are 900-1,100 mS. The short timer is set for a time that will not elapse when a repeated radio frequency message is received, but will expire if a message from the repeated sequence is missing due to interference or the release of a key. The long timer is set for the period in which the requested function should be repeated if a remote key is held indefinitely. The timers are restarted after the radio frequency receiver performs the requested operation of the remote control and runs until the receiver processes a new valid radio frequency command.

In Figure 13, a flow chart is shown to implement the present method. After performing the operation of the above radio frequency message in step 182, the radio frequency receiver controller restarts the short and long timers in step 184 and waits for a new radio frequency message. When a new radio frequency message is detected in step 186, the receiver controller determines whether the long timer has elapsed in step 188. If so, the receiver's controller performs the operation of the new radio frequency message. If not, the receiver controller checks whether the short timer has elapsed in step 190. If not, the receiver's controller returns to step 186 to detect a new valid radio frequency message. If so, the receiver controller checks whether the key pressure status bit has alternated in step 192. If so, the receiver's controller performs the operation of the new radio frequency message. If not, the receiver controller returns to step 186 to detect a new valid radio frequency message. Therefore, it can be seen that the operation for a new radio frequency message is performed if the long timer has elapsed or if the short timer has elapsed and the key pressure status bit in the radio frequency message has alternated to indicate a new key pressure. The present remote control message protocol is suitable for use in the automatic detection of the message format in which a detector is programmed to automatically determine the format, or version, of the message protocol based on the data transmission rate. An automatic format detection method of this type conveniently utilizes the main zero suppression function of the present remote control message protocol. In the principal zero suppression technique, the first transmitted bit is always a logical one, therefore, a signal receiver may be adapted to determine the data transmission rate by measuring the width of the first symbol. Knowing that several data transmission rates correspond to various formats, the associated receiver and processor can be adapted to automatically detect which format is being received and adjust the decoding accordingly. The modality described above, the controller 202 would be programmed to automatically determine the incoming message format by measuring the symbol width 108 of the first symbol after the start sequence 82 in the message 80. The determination of the data rate does not have to be limited to a determination based on a width measurement of the first symbol. The structure of the present remote control message protocol is based on coding of symbols of a basic time interval. Therefore, any part or all of the message can be used to determine the speed and data transmission format, for example, the End of Field marker. Specifically, if you have available memory to store the entire message without decoding it at the moment, you can use many powerful signal processing techniques. Adjusting the data transmission speed can be useful to allow faster formats in the future to be compatible with existing formats. However, it should be understood that the present automatic format detection method is not limited to faster formats. A slower speed implementation could also be used, for example, if the implementation provided a cost advantage. Velocity values may be limited to discrete values or allowed to vary on a continuous scale. In this regard, limiting the velocity values to discrete values may be more convenient than allowing a continuous variable scale for the pulse widths due to ambient noise factors and pulse distortions in the receiver. It will be apparent to those skilled in the art that while the invention has been described in terms of an exemplary embodiment, modifications and changes may be made to the embodiment described without departing from the spirit of the invention. For example, the remote control 10 may be of the universal remote control type which is capable of controlling one of a plurality of electronic devices designed in accordance with a reference code, or other signal format identifying information, selected by the user . The reference code can be selected using, for example, the direct manual input method, the semi-automatic step input method, the automatic input method, or any other suitable method for selecting and inserting a reference code. In that case, the remote control 10 uses the identification information to generate the appropriate signal associated with the particular model and manufacturer. Therefore, it should be understood that the present invention is intended to cover all modifications that are within the true scope and spirit of the present invention.

Claims (10)

1. CLAIMS 1. A remote control apparatus, comprising: an input device (20) for receiving remote control messages from a user; a signal transmitter (16, 17); and a controller (14) operatively coupled to said input device and said signal transmitter, said controller generates a remote control message (80) and causes said signal transmitter to transmit said remote control message in response to the input of the remote control. user, such a remote control message comprises the start sequence (82) followed by a plurality of data fields, each such data field ends with a field marker end (85), said plurality of data fields includes a status field (88) having a message type identifier identifying a particular message protocol, and a key code data field (90) carrying key code data, said key code data being formatted according to such particular message protocol. The remote control apparatus of claim 1, wherein said key code data comprises one of formatted data of standard remote control protocol and ASCI I character data. 3. The remote control apparatus of claim 1, wherein said signal transmitter is a transmitter of the radio frequency signal (17). 4. The remote control apparatus of claim 3, wherein said plurality of data fields additionally comprises a preamble field (86) having data to address a destination device, a security code field (86) having an identifier associated with such a signal transmitter; and a sum check field (92) for verifying the transmission integrity of such a remote control message. The remote control apparatus of claim 1, wherein said start sequence comprises a pulse and a pause period that have substantially the same duration. The remote control apparatus of claim 4, wherein said controller generates said remote control message using principal zero suppression. 7. The remote control apparatus of claim 4, wherein said security code data comprises a three-digit code programmed into said controller by the user. The remote control apparatus of claim 6, wherein said security code data is programmed into said controller using a screen display menu. The remote control apparatus of claim 1, wherein said remote control message additionally comprises an expansion data field (152) and a message marker end, said controller transmits said remote control message in the order of , said start sequence, such plurality of data fields, said expansion data field, and such end of message marker. The remote control apparatus of claim 1, wherein said remote control message additionally comprises a field expansion data field (163) associated with one of said plurality of data fields and a message marker end, said controller transmits such a field expansion data field immediately before said associated data field. eleven . A remote control system comprising: an input device (20) for receiving remote control message from a user; a transmitter of the infrared signal (16); a transmitter of the radio frequency signal (17); and a controller (14) operatively coupled to said input device, said transmitter of the infrared signal and said transmitter of the radio frequency signal, said controller generates an infrared remote control message (80) having intervals of pause and a radio frequency remote control message, said radio frequency remote control message comprises a start sequence (82) having a pulse and a pause period that have substantially the same duration followed by a plurality of data fields, each such data field ends with a field marker end (85), said plurality of data fields includes a status field (88) having a message type identifier that identifies a particular message protocol, and a key code data field (90) carrying key code data, such key code data is formatted according to said particular message protocol, such controller causes such transmitter of the infrared signal and said transmitter of the radio frequency signal transmit such infrared and radio frequency remote control messages wherein the radio frequency remote control message is transmitted during the pause intervals of such infrared remote control message, 12. The remote control apparatus of claim 1, wherein said key code data comprises one of formatted data of standard remote control protocol and character data. ASCI I. The remote control apparatus of claim 1, wherein said radio frequency remote control message is transmitted in the order of, such start sequence (82), a preamble field (84) having data to address to a destination device, a security code field (86) having an identifier associated with such a signal transmitter, said status field, such a key code field, a sum check field (92) for verifying the transmission integrity of such a radio frequency remote control message and an end of the message marker (87). The remote control apparatus of claim 13, wherein said controller generates said radio frequency remote control message using principal zero suppression. 15. The remote control apparatus of claim 13, wherein said security code data comprises a three-digit code programmed into such controller by the user. 16. The remote control apparatus of claim 15, wherein said security code data is programmed into said controller using a screen display menu. 17. A method for transmitting a remote control message, comprising the steps of: receiving a user input through an input device (208); generating an infrared remote control message associated with the user input, the infrared remote control message has pause intervals; generating a radio frequency remote control message (80) corresponding to the user's input, the radio frequency remote control message comprises a start sequence (82) having a pulse and a pause period which have substantially the same duration followed by a plurality of data fields and a message marker end (87), each such data field ends with a field marker end (85), said plurality of data fields comprises a state field (88) having a message type identifier that identifies a particular message protocol, and a key code data field (90) having key code data formatted according to the particular message protocol; transmit infrared and radio frequency remote control messages by transmitting the radio frequency remote control message during the pause intervals of the infrared remote control message. SUMMARY A communications system for transmitting and receiving remote control messages in an electronic remote control system. The present communication system uses a remote control message protocol that is particularly suitable for transmitting radio frequency remote control messages with infrared remote control messages in a time multiplexed manner, wherein the radio frequency remote control messages are transmitted during the pause intervals between the transmission intervals of the infrared remote control message. The present remote control message protocol (80) includes a start sequence (82), which comprises a MARK pulse and a SPACE of approximately the same duration, followed by a plurality of data fields. Each data field ends with a field marker end (85) and the remote control message ends with a message marker end (87). The plurality of data fields comprises an address data field (89) for specifying the destination device, a security code data field (89) for allowing a specific remote control transmitter to control a specific destination device, a status field (88) for specifying various status codes associated with the remote control message, a key code field (90) for transporting the payload of the remote control message, and a sum check field (92). ) to verify the transmission integrity of the remote control message. A remote control message based on the present message protocol can be expanded to include additional data fields and expand pre-existing data fields.