`
`(12) United States Patent
`Mui
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,589,642 B1
`Sep. 15, 2009
`
`(54) RELAYING KEY CODESIGNALS THROUGH
`A REMOTE CONTROL DEVICE
`
`(75) Inventor: Daniel SauFu Mui, San Jose, CA (US)
`(73) Assignee: UEI Cayman Inc. (KY)
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 1076 days.
`(21) Appl. No.: 10/737,029
`
`(22) Filed:
`
`Dec. 16, 2003
`
`(51) Int. Cl.
`(2006.01)
`GOSC 9/00
`(52) U.S. Cl. ............................ 340/825.69; 340/825.72:
`340/825.22; 340/5.61; 340/5.64; 340/5.74;
`340/825.29; 34.5/168
`(58) Field of Classification Search ............ 340/825.69,
`340/825.72, 825.22, 5.61, 5.64, 5.74; 34.5/172,
`345/168; 348/734
`See application file for complete search history.
`References Cited
`
`(56)
`
`U.S. PATENT DOCUMENTS
`5,595,342 A *
`1/1997 McNair et al. ................ 236,51
`5,671,267 A * 9/1997 August et al. ............... 455,420
`5,963,624 A * 10/1999 Pope ..................... 379,110.01
`
`6,747.568 B1* 6/2004 Teskey .................. 340,825.72
`6,819,259 B2 * 1 1/2004 Yamaguchi ............ 340,825.69
`2002/0130803 A1* 9/2002 Conway et al. ............. 341,176
`2005/0151726 A1* 7/2005 Wouters ..................... 345,172
`k .
`cited by examiner
`Primary Examiner Vernal U Brown
`(74) Attorney, Agent, or Firm—Imperium Patents Works:
`Darien K. Wallace
`
`(57)
`
`ABSTRACT
`
`Upon receiving a keystroke indicator signal from a remote
`control device, a key code generator device identifies a
`codeset usable to communicate with a selected consumer
`device. The keystroke indicator signal contains an indication
`of a pressed key, which corresponds to a function of the
`selected consumer device. Using the identified codeset and
`the key indication, the key code generator device generates a
`key code and modulates that key code onto a radio frequency
`carrier signal, thereby generating a first key code signal. The
`remote control device receives the first key code signal from
`the key code generator device and modulates the key code
`onto an infrared frequency carrier signal, thereby generating
`a second key code signal. The remote control device relays
`the key code to the selected consumer device in the second
`key code signal. The key code causes the selected consumer
`device to perform the desired function.
`
`25 Claims, 4 Drawing Sheets
`
`39
`
`OAABASE OF
`CODESETS
`
`10
`
`KEY CODE
`GENERATOR
`RF
`TRANS
`RECEIVER MITTER
`18
`
`DEYCE
`
`
`
`KEYSTROKE
`INDICATOR
`SIGNAL
`16
`
`RF
`TRANSMTR
`17
`
`
`
`
`
`
`19
`FIRS
`221 KEY CODE
`S-23 SIGNAL
`
`
`
`REMOTE
`CONTROL
`
`585
`
`RECEIVER
`
`ELECTRONIC
`CONSUMER
`DEVICE
`
`
`
`Roku EX1001
`U.S. Patent No. 7,589,642
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`
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`U.S. Patent
`
`Sep. 15, 2009
`
`Sheet 1 of 4
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`US 7,589,642 B1
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`39
`
`DATABASE OF
`CODESETS
`
`
`
`
`
`10
`
`38
`
`-35 VIDEON
`
`KEY CODE
`RF GENERATOR
`RF
`DEVICE
`TRANS
`RECEIVER MER 12
`18
`
`
`
`36
`
`KEYSTROKE
`INDICATOR
`SIGNAL
`16
`
`RF
`TRANSMITTER
`
`19
`FIRST
`KEY CODE
`SIGNAL
`
`
`
`
`
`
`
`
`
`REMOTE
`CONTROL
`DEVICE
`
`ES5
`SIGNAL
`
`2 3- - - - - - S- - -
`N
`Y Y 11GHLIGHT DEVICE
`
`a- a
`
`IR
`RECEIVER
`
`ELECTRONIC
`CONSUMER
`DEVICE
`
`FIG. 1
`
`29
`
`
`
`
`
`
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`U.S. Patent
`
`Sep. 15, 2009
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`Sheet 2 of 4
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`US 7,589,642 B1
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`
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`
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`
`
`A CODESET USABLE TO COMMUNICATE WITH AN ELECTRONIC
`CONSUMER DEVICESIDENTIFIED TO A KEY CODE GENERATOR
`DEVICE (FOR EXAMPLE, BY A USER USING AREMOTE CONTROL
`DEVICE AND ANON-SCREEN DISPLAY)
`
`THE USER PRESSESAKEY ON THE REMOTE CONTROL DEVICE, AND A
`CORRESPONDING KEYSTROKE INDICATOR SIGNALS SENT TO THE
`KEY CODE GENERATORDEVICE, THE KEY CORRESPONDS TO A
`DESIRED FUNCTION OF THE ELECTRONIC CONSUMER DEVICE
`
`100
`
`101
`
`THE KEY CODE GENERATOR DEVICE USES THE DENTIFIED CODESET
`TO GENERATEA KEY CODE CORRESPONDING TO THE PRESSED KEY
`
`102
`
`THE KEY CODE GENERATOR DEVICE MODULATES THE KEY CODE
`ONTO A FIRST CARRIER SIGNAL (FOR EXAMPLE, ANRF SIGNAL),
`THEREBY GENERATING A FIRST KEY CODESIGNAL
`
`THE FIRST KEY CODESIGNAL STRANSMITTED FROM THE KEY CODE
`GENERATOR DEVICE AND TO THE REMOTE CONTROL DEVICE
`
`THE REMOTE CONTROL DEVICE RECEIVES THE FIRST KEY CODE
`SIGNAL AND RELAYS THE KEY CODE BY TRANSMITTING THE KEY
`CODE IN A SECOND KEY CODESIGNAL THE SECOND KEY CODE
`SIGNAL USESA SECOND CARRIER SIGNAL (FOR EXAMPLE, ANR
`SIGNAL) TO CARRY THE KEY CODE
`
`103
`
`104
`
`105
`
`THE SECOND KEY CODESIGNAL IS RECEIVED ONTO THE ELECTRONIC
`CONSUMER DEVICE
`
`106
`O
`
`THE KEY CODE CAUSES THE ELECTRONIC CONSUMER DEVICE TO
`PERFORM THE DESIRED FUNCTION
`
`107
`
`END
`
`FIG. 2
`
`
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`U.S. Patent
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`Sep. 15, 2009
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`Sheet 3 of 4
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`US 7,589,642 B1
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`0 1 0 1 0 0 0 1 1 1 0 O
`
`SYSTEM
`CODE
`
`KEY DATA
`
`KEY CODE
`FIG. 3
`
`MARK SPACE
`LENGTH LENGTH
`
`is Ec --
`
`MARK
`LENGTH
`394 BURSTS
`-3940 usec-> --2000 usec->
`
`SPACE
`LENGTH
`
`-- 1000
`t DIGITAL "O"
`49
`BURSTS
`
`2000
`
`3000
`
`5000
`4000
`DIGITAL "1"
`FIG. 6A
`
`6000
`
`usec
`7OOO
`
`6
`4.
`usec
`usec
`INTERMEDIARY---- - -NTERMEDIARY
`SIGNAL ON TIME
`El SIGNAL OFF TIME
`
`490 usec
`49 BURSTS
`-
`
`N- - - - - - - - -
`MARK LENGTH
`OF DIGITAL "O"
`
`- - - - - - -1
`
`FIG. 6B
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`
`
`U.S. Patent
`U.S. Patent
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`Sep. 15, 2009
`Sep. 15, 2009
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`Sheet 4 of 4
`Sheet 4 of 4
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`US 7,589,642 B1
`US 7,589,642 B1
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`
`1.
`RELAYING KEY CODESIGNALS THROUGH
`A REMOTE CONTROL DEVICE
`
`US 7,589,642 B1
`
`TECHNICAL FIELD
`
`The present invention relates generally to remote control
`devices and, more specifically, to relaying key code signals
`through a remote control device to operate an electronic con
`Sumer device.
`
`BACKGROUND
`
`10
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`2O
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`Most households today possess multiple types of elec
`tronic consumer devices, such as televisions, Stereo radios,
`digital video disk players, video cassette recorders, set-top 15
`cable television boxes and set-top satellite boxes. Manufac
`turers of Such electronic devices typically supply a remote
`control device along with each electronic device. It is, there
`fore, common for a consumer who has multiple electronic
`devices to have multiple remote control devices.
`A remote control device typically controls a selected elec
`tronic consumer device by transmitting infrared key code
`signals to the selected electronic consumer device. The infra
`red signals contain key codes of a codeset associated with the
`selected electronic consumer device. Each key code corre- 25
`sponds to a function of the selected electronic device, such as
`power on, power off, Volume up, Volume down, play, stop,
`select, channel up, channel down, etc. In order to avoid the
`situation where a remote control device unintentionally oper
`ates an electronic consumer device that is associated with a 30
`different remote control device, manufacturers sometimes
`use distinct codesets for the communication between various
`electronic consumer devices and their associated remote con
`trol devices. The codesets can differ from each other not only
`by the bit patterns assigned to various functions of the asso- 35
`ciated electronic consumer device, but also by the timing
`information that describes how the key codes should be
`modulated onto carrier signals to generate key code signals.
`Consumers may find it inconvenient to operate their elec
`tronic devices using multiple remote control devices. Thus, a 40
`consumer may wish to operate multiple electronic consumer
`devices using a single remote control device. A single remote
`control device can store many codesets so that the remote
`control device can control a corresponding large number of
`different electronic consumer devices. There are, however, 45
`thousands of codesets in use in electronic consumer devices
`today. Manufacturers of remote control devices, however,
`may wish to limit the memory on their remote control devices
`to a size that is insufficient to store the thousands of existing
`codesets.
`A system is sought for enabling a remote control device to
`control a selected one of multiple different electronic con
`Sumer devices without requiring the codeset associated with
`the selected electronic consumer device to be stored on the
`remote control device.
`
`50
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`55
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`SUMMARY
`
`A system for relaying a key code through a remote control
`device to an electronic consumer device allows the electronic 60
`consumer device to be controlled without storing the associ
`ated codeset on the remote control device. Upon receiving a
`keystroke indicator signal from a remote control device, a key
`code generator device, such as a set-top box, identifies the
`particular codeset usable to communicate with the selected 65
`electronic consumer device. The keystroke indicator signal
`contains an indication of a key on the remote control device
`
`2
`that was pressed, which corresponds to a function of the
`selected electronic consumer device. Using the identified
`codeset and the indication of the pressed key, the key code
`generator device generates a key code and modulates that key
`code onto a radio frequency carrier signal, thereby generating
`a first key code signal. The remote control device receives the
`first key code signal from the key code generator device and
`modulates the key code onto an infrared frequency carrier
`signal, thereby generating a second key code signal. The
`remote control device relays the key code to the selected
`electronic consumer device in the second key code signal.
`The key code causes the selected electronic consumer device
`to perform the desired function. The key code is not stored on
`the remote control device in a permanent manner, but rather
`the key code is relayed through the remote control device.
`In another embodiment, a third key code signal (which
`may, for example, be a radio frequency signal) is communi
`cated directly from the key code generator device to an elec
`tronic consumer device. A key code contained in the third key
`code signal causes the electronic consumer device to perform
`a desired function.
`In yet another embodiment, the system automatically
`determines which codeset is usable to communicate with a
`selected electronic consumer device. The key code generator
`device sends key codes for one particular function from
`among a series of codesets one-by-one to the selected elec
`tronic consumer device. When the key code from one of the
`codesets causes the electronic consumer device to perform
`the desired function, electromagnetic noise is introduced into
`electrical power wiring through which both the electronic
`consumer device and the key code generator device receive
`power. When the key code generator device detects this noise
`on the electrical power wiring, the key code generator device
`identifies the codeset corresponding to the last transmitted
`key code to be the codeset usable to communicate with the
`selected electronic consumer device.
`Other embodiments and advantages are described in the
`detailed description below. This summary does not purport to
`define the invention. The invention is defined by the claims.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The accompanying drawings, where like numerals indicate
`like components, illustrate embodiments of the invention.
`FIG. 1 is a schematic diagram of a system for relaying key
`code signals through a remote control device.
`FIG. 2 is a flowchart of a method for relaying key code
`signals through a remote control device.
`FIG. 3 is an illustration of a key code transmitted within a
`key code signal.
`FIG. 4 is a waveform diagram of a first example of a key
`code signal transmitted by a remote control device in the
`system of FIG. 1.
`FIG. 5 is a waveform diagram of a second example of a key
`code signal transmitted by a remote control device in the
`system of FIG. 1.
`FIG. 6A is an illustration of a modulated digital Zero and
`digital one within the key code signal of FIG. 5.
`FIG. 6B is a more detailed illustration of a mark of a
`modulated digital Zero within the key code signal of FIG. 5.
`
`DETAILED DESCRIPTION
`
`Reference will now be made in detail to some embodi
`ments of the invention, examples of which are illustrated in
`the accompanying drawings.
`
`
`
`3
`FIG. 1 is a diagram of a system 10 for relaying a key code
`through a remote control device 11 to an electronic consumer
`device in accordance with the present invention. FIG. 2 is a
`flowchart that illustrates a method of operation of system 10.
`System 10 includes a key code generator device 12, remote
`control device 11, a first electronic consumer device 13 and a
`second electronic consumer device 14. In this example, sec
`ond electronic consumer device 14 is a television set.
`In a first step (step 100), key code generator device 12
`determines the appropriate codeset that controls the type,
`brand and model of the particular electronic consumer device
`that is to be controlled. A user uses remote control device 11
`to respond to an on-screen display 15 on the screen of televi
`sion set 14 to step through a sequence of menu screens to
`identify the codeset corresponding to the device that is to be
`controlled. The user does this by identifying, on on-screen
`display 15, the type, brand and model of the particular elec
`tronic consumer device. In this example, the user is identify
`ing first electronic consumer device 13, which is a video
`cassette recorder (VCR) manufactured by Sony with model
`number 8000. In FIG. 1, the user is identifying the device type
`by highlighting the choice “VCR' on the on-screen display.
`In another example, subsequent to controlling VCR 13, the
`user may wish to control television set 14, which is a “Gold
`model manufactured by RCA. In that case, the user begins
`identifying television set 14 by highlighting the choice “TV”.
`In the present example, key code generator device 12 is a
`set-top box. Key code generator device 12 generates the on
`screen displays and communicates with television set 14 Such
`that key code generator device 12 identifies one of a plurality
`of codesets that corresponds to one of the electronic con
`Sumer devices identified by the user, such as VCR 13 or
`television set 14. System 10 uses the appropriate codeset to
`enable remote control device 11 to communicate with VCR
`13 and television set 14.
`35
`Next (step 101), the user presses a key on remote control
`device 11. This key is associated with a function that the user
`wants performed by an electronic consumer device. For
`example, the function may be to turn on the power of VCR 13.
`When the user presses the “VCR power-on' key on remote
`control device 11, remote control device 11 transmits a key
`stroke indicator signal 16 from a radio frequency (RF) trans
`mitter 17 on remote control device 11. Alternatively, two or
`more keys on remote control device 11 may be associated
`with a single function, Such as turning on the power of VCR
`45
`13. In that case, the user presses a “VCR key and then a
`“power-on' key to cause remote control device 11 to transmit
`keystroke indicator signal 16. Keystroke indicator signal 16 is
`transmitted as a signal in a radio frequency band to an RF
`receiver 18 on key code generator device 12.
`There are multiple forms in which an indication of the
`pressed key, as well as the identity of the electronic consumer
`device that is to perform the associated function, can be
`communicated in keystroke indicator signal 16 from remote
`control device 11 to key code generator device 12. In one
`embodiment, the indication of the pressed key is a key code
`comprised of a standardized system code and Standardized
`key data. In the present example, the standardized system
`code identifies the type of electronic consumer device that is
`to be controlled, such as a TV, a VCR, a DVD player, a stereo
`amplifier, a satellite receiver or a cable receiver. The standard
`ized system code and key data are part of a commonly used
`codeset that is stored on remote control device 11. Remote
`control device 11 uses any one of a number of commonly used
`modulation techniques to modulate the system code and key
`data to form keystroke indicator signal 16. For example, a
`microcontroller on remote control device 11 uses timing
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`information associated with the commonly used codeset to
`generate a pulse width modulated keystroke indicator signal
`16.
`In another embodiment, the indication of the pressed key
`includes a proprietary identification code identifying the
`pressed key, as well as a proprietary identification code cor
`responding to the type of the electronic consumer device that
`is to be controlled. The proprietary identification codes are
`understood by key code generator device 12, but are not
`standardized codes that are understood by electronic con
`Sumer devices. Remote control device 11 uses any one of a
`number of commonly used modulation techniques to modu
`late the proprietary identification codes onto keystroke indi
`cator signal 16.
`Whether remote control device 11 communicates with key
`code generator device 12 through a standardized codeset or
`through proprietary identification codes, codes may be
`included that do not correspond to pressed keys or functions
`that are to be performed on electronic consumer devices. For
`example, in response to receiving any signal from remote
`control device 11, key code generator device 12 may return a
`code to remote control device 11 causing a light emitting
`diode (LED) display on remote control device 11 to turn on.
`Next (step 102), key code generator device 12 determines
`which key code of the codeset previously identified in step
`100 corresponds to the pressed key.
`FIG. 3 illustrates one example of a key code from a com
`monly used codeset. The key code is comprised of a standard
`ized system code and standardized key data. Both the system
`code and the key data are digital values. The 12-bit key code
`includes a 4-bit system code 01 01 and 8-bit key data
`00011100). In the present example, the key code is the key
`code in the identified codeset that corresponds to the “VCR
`power-on' key of remote control device 11.
`Next (step 103), key code generator device 12 modulates
`the key code for the power-on function of VCR 13 onto a first
`carrier signal, thereby generating a first key code signal 19. In
`this example, the first carrier signal is an RF signal. An RF
`signal for purposes of this patent document is an electromag
`netic signal having a frequency between thirty hertz and three
`hundred gigahertz.
`FIG. 4 and FIG. 5 illustrate key code signal 19 in two
`specific embodiments. In both embodiments, the key code is
`transmitted as a stream of digital values 01 0100011100,
`where the system code is transmitted first immediately fol
`lowed by the key data without any place holders between
`them. The standardized system code determined in step 102
`need not identify the brand or model of VCR 13, but only the
`fact that first electronic consumer device 13 is a VCR. The key
`code is modulated in step 103 using timing information asso
`ciated with the codeset for VCR 13. Thus, the particular brand
`and model of VCR 13 is able to understand the key code
`modulated using the appropriate timing information.
`In the embodiment of FIG.4, key code signal 19 is a 15-bit
`binary transmission whose bit pattern appears as a universal
`asynchronous receiver and transmitter (UART) type commu
`nication. The binary transmission begins with a start bit and
`ends with a parity bit and a stop bit. The parity bit is calculated
`based on the 12-bit key code within the binary transmission.
`In this example, the value of the parity bit is a digital zero. An
`intermediary signal is transmitted over the first carrier signal
`at an intermediary frequency (for example, 100 kHz) to com
`municate a digital one. The absence of the intermediary signal
`indicates a digital Zero. The intermediary signal has a lower
`frequency than the first carrier signal.
`In the embodiment of FIG. 5, the 12-bit key code is modu
`lated onto key code signal 19 using pulse width modulation.
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`US 7,589,642 B1
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`5
`Digital ones and Zeros are characterized by pairs of marks and
`spaces. The period between Successive leading edges of the
`bursts in a mark is the period of an intermediary signal. The
`intermediary signal has an intermediary frequency. In a space,
`there are no bursts.
`FIG. 6A shows a digital Zero and a digital one in key code
`signal 19 of FIG. 5 in more detail. A “mark/space' pair
`represents a digital Zero and another “mark/space’ pair rep
`resents a digital one. The marks and spaces of each pair have
`predetermined lengths. In the embodiment of FIG. 5, the 10
`mark length of a digital Zero is 490 microseconds, and the
`mark length of a digital one is 3940 microseconds. The space
`length of a digital Zero is 950 microseconds, and the space
`length of a digital one is 2000 microseconds.
`FIG. 6B shows the bursts of the first carrier signal that 15
`comprise the intermediary signal in more detail. In the
`embodiment of FIG. 5, the bursts that comprise the interme
`diary signal occur every ten microseconds, resulting in an
`intermediary frequency of 100 kilohertz. The duty cycle of
`the intermediary signal is characterized by an “on time' of 20
`four microseconds and an "off time' of six microseconds.
`There are forty-nine bursts of the carrier signal within each
`mark length of 490 microseconds.
`Timing information other than that shown in the embodi
`ment of FIG. 5 can also be used. For example, one common 25
`form of pulse width modulation uses an intermediary signal
`having a frequency of about 38.5 kilohertz. Each period of the
`intermediary signal has an “on time often microseconds and
`an "off time' of sixteen microseconds. If such an intermedi
`ary signal were used to generate a 490 microsecond mark 30
`length of a digital Zero shown in FIG. 6A, there would be 19
`bursts of the intermediary signal in the mark. Similarly, if
`Such an intermediary signal were used to generate a 3940
`microsecond mark length of a digital one shown in FIG. 6A,
`there would be 151 bursts of the intermediary signal in the
`mark.
`Next (step 104), an RF transmitter 20 of key code generator
`device 12 transmits first key code signal 19 in the form of an
`RF transmission to an RF receiver 21 on remote control
`device 11.
`Next (step 105), remote control device 11 receives first key
`code signal 19 and relays the key code communicated by first
`key codesignal 19 to VCR 13 in the form of a second key code
`signal 22. Remote control device 11 is a slave to key code
`generator device 12. Remote control device 11 relays the key
`code by receiving first key code signal 19 in RF form and
`translating the communicated key code so that the key code is
`modulated onto a second carrier signal resulting in second
`key code signal 22. In this example, the second carrier signal
`is an infrared signal with a frequency in the range between
`three hundred gigahertz and three hundred terahertz. Second
`key code signal 22 is transmitted by an IR transmitter 23 on
`remote control device 11 to VCR 13. In the embodiment of
`FIG. 5, key codesignal 19 is converted into key codesignal 22
`by forming the bursts of the intermediary signal using the
`second carrier signal with an infrared frequency in the place
`of the first carrier signal with a radio frequency. For both key
`codesignal 19 and key codesignal 22, digital ones and digital
`Zeros are modulated using the same timing for “mark/space”
`pairs. The waveform diagram of key code signal 22 appears
`the same as the waveform diagram shown in FIG. 5 for key
`code signal 19; only the frequency of the carrier signal that
`forms the bursts is different.
`Next (step 106), second key code signal 22 is received onto
`electronic consumer device (VCR) 13 by an IR receiver 24.
`Next (step 107), IR receiver 24 on VCR 13 recovers the key
`code from second key code signal 22. VCR 13 is thereby
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`instructed to perform the function desired by the user. In this
`example, the function is to power on VCR 13. Other key
`codes, however, correspond to other functions, such as power
`off, channel advance, channel back, Volume up, Volume
`down, cursor up, cursor down, cursor right, cursor left, select,
`play, record, Stop, forward, rewind and pause.
`In a second example, an electronic consumer device is
`controlled by an RF key code signal transmitted from key
`code generator device 12. Subsequent to controlling VCR 13,
`the user wishes to control second electronic consumer device
`14, which is a "Gold' model RCA television set. In the second
`example, the useruses the on-screen display 15 to identify the
`type (TV), brand (RCA) and model (Gold) of second elec
`tronic consumer device 14. Key code generator device 12
`determines the appropriate codeset that controls television set
`14. The user then presses a key on remote control device 11
`associated with a function that the user wants performed by
`television set 14. For example, the function is to advance the
`channel of television set 14. When the user presses the chan
`nel advance key on remote control device 11, an indication of
`the pressed key is transmitted in an RF keystroke indicator
`signal from remote control device 11 to key code generator
`device 12.
`Key code generator device 12 then determines which key
`code of the identified codeset corresponds to the pressed key.
`Key code generator device 12 modulates the key code for the
`channel advance function onto an RF carrier signal, thereby
`generating a third key code signal 25. Key code generator
`device 12 uses the same modulation technique to generate
`both third key code signal 25 and first key code signal 19.
`Third key code signal 25 is modulated using timing informa
`tion associated with the codeset that controls RCA Gold
`television set 14.
`In this second example, television set 14 has an RF receiver
`26 and is capable of receiving RF key codesignals. RF trans
`mitter 20 of key code generator device 12 transmits third key
`code signal 25 directly to television set 14. Third key code
`signal 25 is received onto television set 14 by RF receiver 26,
`and RF receiver 26 recovers the key code from third key code
`signal 25. Television set 14 is thereby instructed to advance
`the channel.
`Although remote control device 11 in the first example
`stores either a proprietary codeset or a standardized codeset
`and uses that codeset to generate keystroke indicator signal
`16, remote control device 11 stores only that single codeset.
`This codeset is the codeset used by key code generator device
`12 to receive communications from remote control device 11.
`Remote control device 11 can therefore be made inexpen
`sively and may contain a relatively small amount of memory.
`The memory may, for example, be read only memory (ROM)
`on a microcontroller integrated circuit (for example, a Z8
`microcontroller available from Zilog, Inc. of San Jose, Calif.)
`Even though remote control device 11 stores only a single
`codeset, system 10 of FIG. 1 nevertheless allows remote
`control device 11 to control the desired electronic consumer
`device 13, which may use any one of thousands of different
`codesets. Key code generator device 12 may, for example,
`include a hard disk or other mass storage device that stores
`thousands of possible codesets. The user may use remote
`control device 11 to select any one of those codesets for
`communication with the particular electronic consumer
`device 13. In comparison to Some conventional systems
`where codesets are downloaded into a universal remote con
`trol device from a personal computer or other device that is
`not normally part of an entertainment system, system 10 uses
`preexisting hardware of the entertainment system (such as the
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`on-screen display functionality, data storage capability, and
`wireless communication ability of the set-top box) to Source
`and identify codesets.
`Although the specific embodiments of FIGS. 1 and 2 are
`explained above in connection with the codesets being iden
`tified to the key code generator device 12 using an on-screen
`display, the codeset usable to communicate with an electronic
`consumer device may be identified to key code generator
`device 12 in other ways in other embodiments. In one
`embodiment, for example, the key code generator device
`includes autoscan functionality. Key code generator device
`12 includes an EMI detector 27 that detects electromagnetic
`interference (EMI) or noise on power cord 28. Power cord 28
`is a power cord through which key code generator device 12
`receives electrical power from a wall socket 29. Similarly,
`television set 14 receives power from another wall socket 30
`via a power cord 31. VCR 13 receives power from a wall
`socket 32 via another power cord 33. In accordance with the
`autoscan functionality, key code generator device 12 identi
`fies the codeset used to communicate with a particular elec
`tronic consumer device by generating and transmitting a
`sequence of key code signals relayed through remote control
`device 11 to the electronic consumer device to be controlled
`(in this case VCR 13). Each of these key codesignals contains
`a different key code corresponding to the same desired func
`tion on different device types, brands and models.
`In one example, the desired function is the function of
`powering on VCR 13. The key code generator device 12 sends
`the power-on key codes for each of a series of codesets one
`by-one to VCR 13. When the key code for one of the codesets
`causes VCR 13 to perform the desired function (in this case,
`to power on), VCR 13 introduces noise or other electromag
`netic interference via cord 33 into wall socket 32. The power
`terminal within wall socket 32 is connected through wiring 34
`to the power terminal in wall socket 29. The noise generated
`by VCR 13 is therefore communicated through wiring 34, the
`power terminal of wall socket 29 and power cord 28 to EMI
`detector 27 on key code generator device 12. When key code
`generator device 12 detects the electromagnetic interference
`on power cord 28, key code generator device 12 automatically
`identifies the codeset used by VCR 13 as the codeset used to
`communicate the last key code signal for the power-on func
`tion.
`Multiple electronic consumer devices may have the same
`key data for a particular function, for example, the power-on
`function. A key code, however, also contains a system code
`(see FIG. 3) that corresponds to a particular type of electronic
`consumer device. For example, the system code used for a
`television set will typically be different than the system code
`used for a video cassette recorder. Thus, different device types
`that use the same key data for the power-on function will not
`respond to a key code containing an incorrect system code.
`Each of the power-on key codes transmitted in this example
`by key code generator device 12 contains the system code for
`a video cassette recorder, so television set 14 does not recog
`nize the key codes. Because key code generator device 12 is
`aware of the system code communicated, key code generator
`device 12 determines that it was VCR 13 that was powered on
`and not television 14.
`In another example, the codeset usable to communicate
`with VCR 13 is identified to key code generator device 12
`using autoscan functionality that does not involve key code
`generator device 12 having a specialized EMI detection cir
`cuit. In that case, the user may be prompted by Successive
`screens of on screen display 15 to push the power-on key on
`remote control device 11 multiple times. Each time the
`power-on key is pressed, keystroke indicator signal 16 com
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`municates this to key code generator device 12. Key code
`generator device 12 in turn generates and transmits a key code
`signal containing a power-on key code using a different
`codeset. Each key code signal is relayed through remote
`control device 11 to the particular electronic consumer device
`to be controlled. One by one the user is prompted to push the
`power-onkey, and key code generator device 12 in turn gen
`erates key codes using different codesets until the electronic
`consumer device performs a desired function. In this case,
`first electronic consumer device 13 turns on. The user is
`prompted not to press the power-onkey once the user sees the
`desired function being performed by first electronic con
`S