`
`1111111111111111111111111111111111111111111111111111111111111
`US009911325B2
`
`c12) United States Patent
`Mui
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 9,911,325 B2
`Mar.6,2018
`
`(54) RELAYING KEY CODE SIGNALS THROUGH
`A REMOTE CONTROL DEVICE
`
`(71) Applicant: Universal Electronics Inc., Santa Ana,
`CA (US)
`
`(58) Field of Classification Search
`CPC ........ GOSC 15/04; GOSC 17/02; GOSC 23/04;
`GOSC 19/28
`USPC ....................................................... 340/13.24
`See application file for complete search history.
`
`(72)
`
`Inventor: Daniel SauFu Mui, San Jose, CA (US)
`
`(56)
`
`References Cited
`
`(73) Assignee: Universal Electronics Inc., Santa Ana,
`CA (US)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 15/153,905
`
`(22) Filed:
`
`May 13, 2016
`
`(65)
`
`Prior Publication Data
`
`US 2016/0253899 Al
`
`Sep. 1, 2016
`
`(63)
`
`(51)
`
`(52)
`
`Related U.S. Application Data
`
`Continuation of application No. 13/068,820, filed on
`May 21, 2011, now Pat. No. 9,355,553, which is a
`continuation of application No. 12/462,526, filed on
`Aug. 4, 2009, now Pat. No. 8,004,389, which is a
`continuation of application No. 10/737,029, filed on
`Dec. 16, 2003, now Pat. No. 7,589,642.
`
`Int. Cl.
`G08C 23104
`G08C 17100
`G08C 15104
`G08C 17102
`G08C 19128
`U.S. Cl.
`CPC
`
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`
`G08C 23104 (2013.01); G08C 15104
`(2013.01); G08C 17100 (2013.01); G08C
`17102 (2013.01); G08C 19128 (2013.01)
`
`U.S. PATENT DOCUMENTS
`
`4,242,664 A * 12/1980 Lindstedt
`
`5,724,106 A * 3/1998
`
`Autry.
`
`5,963,624 A * 10/1999
`6,915,109 B2 * 7/2005 Wouters
`
`H03J 9/06
`340/12.18
`G06F 3/0213
`3411176
`Pope . ................... H04M 111007
`348/734
`G08C 17/02
`455/142
`
`(Continued)
`
`Primary Examiner- Vernal Brown
`(74) Attorney, Agent, or Firm- Greenberg Traurig, LLP
`
`(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.
`
`16 Claims, 4 Drawing Sheets
`
`START
`
`A CODESET USABLE TO COMMUNICATE WITH AN ELECTRONIC CONSUMER DEVICE IS
`IDENTIFIED TO A KEY CODE GENERATOR DEVICE (FOR EXAMPLE, BY A USER USING A
`REMOTE CONTROL DEVICE AND AN ON-SCREEN DISPLAY)
`
`THE USER PRESSES A KEY ON THE REMOTE CONTROl DEVICE, AND A
`CORRESPONDING KEYSTROKE INDICATOR SIGNAL IS SENT TO THE KEY CODE
`GENERATOR DEVICE, THE KEY CORRESPONDS TO A DESIRED FUNCTION OF THE
`ELECTRONIC CONSUMER DEVICE
`
`THE KEY CODE GENERATOR DEVICE USES THE IDENTIFIED CODESETTO GENERATE A
`KEY CODE CORRESPONDING TO THE PRESSED KEY
`
`THE KEY CODE GENERATOR DEVICE MODULATES THE KEY CODE ONTO A FIRST
`CARRIER SIGNAL (FOR EXAMPLE, AN RF SIGNAL), THEREBY GENERATING A FIRST KEY
`CODE SIGNAL
`
`THE FIRST KEY CODE SIGNAL IS TRANSMITTED 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 CODE SIGNAL, THE
`SECOND KEY CODE SIGNAL USES A SECOND CARRIER SIGNAL (FOR EXAMPLE, AN IR
`SIGNAL) TO CARRY THE KEY CODE
`
`THE SECOND KEY CODE SIGNAL IS RECEIVED ONTO THE ELECTRONIC CONSUMER
`DEVICE
`
`THE KEY CODE CAUSES THE ELECTRONIC CONSUMER DEVICE TO PERFORM THE
`DESIRED FUNCTION
`
`END
`
`Roku EX1001
`U.S. Patent No. 9,911,325
`
`
`
`US 9,911,325 B2
`Page 2
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`7,266,834 Bl * 9/2007 Lund .
`
`* cited by examiner
`
`H04M 11575
`725/106
`
`
`
`U.S. Patent
`
`Mar.6,2018
`
`Sheet 1 of 4
`
`US 9,911,325 B2
`
`39
`
`DATABASE OF
`CODESETS
`
`10~
`
`f-3s VIDEO IN
`
`36
`
`14
`
`/>::;/
`">..----,
`15
`/::;/,...____
`;"HIGHLIGHT DEVICE :
`\TYPE:
`I
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`I TV :::V~.:::: DVD
`\
`' AMP SAT CABLE
`'
`/THEN PRESS SELECT.)
`---------/
`-
`:U. ?//
`
`/
`
`/
`
`29
`
`34
`
`30
`
`24
`IR
`RECEIVER
`
`13
`ELECTRONIC
`CONSUMER
`DEVICE
`
`FIG. 1
`
`KEYSTROKE
`INDICATOR
`SIGNAL
`16
`
`11
`REMOTE
`CONTROL
`DEVICE
`
`
`
`U.S. Patent
`
`Mar.6,2018
`
`Sheet 2 of 4
`
`US 9,911,325 B2
`
`( START )
`
`+
`
`A CODESET USABLE TO COMMUNICATE WITH AN ELECTRONIC CONSUMER DEVICE IS
`IDENTIFIED TO A KEY CODE GENERATOR DEVICE (FOR EXAMPLE, BY A USER USING A
`REMOTE CONTROL DEVICE AND AN ON-SCREEN DISPLAY)
`
`'""""' 100
`
`~
`THE USER PRESSES A KEY ON THE REMOTE CONTROL DEVICE, AND A
`CORRESPONDING KEYSTROKE INDICATOR SIGNAL IS SENT TO THE KEY CODE
`GENERATOR DEVICE, THE KEY CORRESPONDS TO A DESIRED FUNCTION OF THE
`ELECTRONIC CONSUMER DEVICE
`~
`THE KEY CODE GENERATOR DEVICE USES THE IDENTIFIED CODESET TO GENERATE A
`KEY CODE CORRESPONDING TO THE PRESSED KEY
`~
`THE KEY CODE GENERATOR DEVICE MODULATES THE KEY CODE ONTO A FIRST
`CARRIER SIGNAL (FOR EXAMPLE, AN RF SIGNAL), THEREBY GENERATING A FIRST KEY
`CODE SIGNAL
`
`+
`
`THE FIRST KEY CODE SIGNAL IS TRANSMITTED 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 CODE SIGNAL, THE
`SECOND KEY CODE SIGNAL USES A SECOND CARRIER SIGNAL (FOR EXAMPLE, AN IR
`SIGNAL) TO CARRY THE KEY CODE
`
`~
`THE SECOND KEY CODE SIGNAL IS RECEIVED ONTO THE ELECTRONIC CONSUMER
`DEVICE
`
`+
`
`THE KEY CODE CAUSES THE ELECTRONIC CONSUMER DEVICE TO PERFORM THE
`DESIRED FUNCTION
`~
`l END J
`
`'""""' 101
`
`,.._.. 102
`
`...._... 103
`
`104
`'""""'
`
`...._... 105
`
`'""""' 106
`
`...._...
`
`107
`
`FIG. 2
`
`
`
`U.S. Patent
`
`Mar.6,2018
`
`Sheet 3 of 4
`
`US 9,911,325 B2
`
`0 1 0 1 0 0 0 1 1 1 0 0
`
`~----~~----
`SYSTEM
`KEY DATA
`CODE
`KEY CODE
`FIG. 3
`
`SPACE
`MARK
`MARK SPACE
`LENGTH
`LENGTH
`LENGTH LENGTH
`~~~---------------~--------------~-------~~------~
`394 BURSTS
`I
`I
`.,..490.,.- 950 _......_-----------3940 J.lSSC-------------2000 J.lS9C-l
`J.lS9C
`J.lS9C
`I
`
`I
`I
`I
`I
`I
`I
`I
`
`I
`~ 1000 J'-_2_o_o_o ______ 3_o_oo _______ 4o_o_o __ ~ __ s_o_oo _______ 6_oo_o ________ __
`
`\ DIGI"rAL "0"
`49
`BURSTS
`
`DIGITAL "1"
`
`FIG. 6A
`
`4
`J.lS9C
`II
`INTERMEDIARY -+it(cid:173)
`SIGNAL ON TIME
`II
`II
`
`6
`J.lS9C
`II
`-+!!+-INTERMEDIARY
`II SIGNAL OFF TIME
`II
`
`~----------------------490)-lSSC---------------------
`49 BURSTS
`
`MARK LENGTH
`OF DIGITAL "0"
`
`FIG. 68
`
`
`
`N u. = N
`
`""""' w
`""""'
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`'"'..c
`
`rJl
`d
`
`0 .....
`
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`
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`
`.....
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`
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`
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`~ :-:
`~
`
`0 ....
`
`QO
`
`~ = ~
`
`~
`~
`~
`•
`00
`
`e •
`
`15
`
`12 13 14
`
`11
`
`..--"-v-J~
`
`A
`
`10
`
`..-
`
`5 msec
`
`4
`
`A
`
`3
`
`9
`
`..-
`
`_.......,,_...._..~
`
`BIT
`PARITY STOP
`
`I
`
`oo/
`BIT
`
`...
`1
`
`v
`
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`1
`
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`
`KEY DATA
`
`15
`
`14
`
`13
`
`12
`
`11
`
`10
`
`9
`
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`
`I
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`
`BIT
`PARITY STOP
`
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`BIT
`
`o
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`
`1
`
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`
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`
`KEY DATA
`
`.•• ~· ~~~~· .,., ~~~~··
`
`~-------~~~ ...
`1
`
`ooo
`
`1
`
`o
`
`FIG. 5
`
`PULSE WIDTH MODULATION
`5
`
`6 7 8
`
`4
`
`3
`
`2
`
`BIT NUMBER
`
`1
`
`~_,____~---.,.._,, ............. ......._..,
`
`2
`
`1
`
`o
`
`~
`
`19
`
`KEY CODE
`
`SIGNAL
`
`SYSTEM DATA
`
`START
`
`I I I I I I . . I . . I . . I I
`I
`
`o
`
`o
`
`o
`
`1
`
`o
`
`1
`
`o
`
`SYSTEM DATA
`
`19~
`
`KEY CODE
`
`SIGNAL
`
`START
`
`BIT
`
`FIG. 4
`
`BINARY TRANSMISSION
`
`8
`
`7
`
`6
`
`5
`
`4
`
`3
`
`2
`
`BIT NUMBER
`
`I
`
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`
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`
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`
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`
`1
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`
`(
`BIT
`
`
`
`US 9,911,325 B2
`
`1
`RELAYING KEY CODE SIGNALS THROUGH
`A REMOTE CONTROL DEVICE
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`
`2
`consumer devices without requiring the codeset associated
`with the selected electronic consumer device to be stored on
`the remote control device.
`
`SUMMARY
`
`This application is a continuation of and claims the benefit
`of U.S. application Ser. No. 13/068,820, filed on May 21,
`2011, which application is a continuation of and claims the
`benefit of U.S. application Ser. No. 12/462,526, filed on
`Aug. 4, 2009, which application is a continuation of and
`claims the benefit of U.S. application Ser. No. 10/737,029,
`filed on Dec. 16, 2003, each of which is incorporated herein
`by reference in its entirety.
`
`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
`consumer device.
`
`BACKGROUND
`
`15
`
`A system for relaying a key code through a remote control
`device to an electronic consumer device allows the elec(cid:173)
`tronic consumer device to be controlled without storing the
`10 associated 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 electronic consumer device. The keystroke
`indicator signal contains an indication of a key on the remote
`control device 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,
`20 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
`25 infrared frequency carrier signal, thereby generating a sec(cid:173)
`ond 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.
`30 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 commu-
`35 nicated directly from the key code generator device to an
`electronic 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
`40 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
`electronic consumer device. When the key code from one of
`45 the codesets causes the electronic consumer device to per(cid:173)
`form the desired function, electromagnetic noise is intro(cid:173)
`duced 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
`50 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
`55 detailed description below. This summary does not purport
`to define the invention. The invention is defined by the
`claims.
`
`Most households today possess multiple types of elec(cid:173)
`tronic consumer devices, such as televisions, stereo radios,
`digital video disk players, video cassette recorders, set-top
`cable television boxes and set-top satellite boxes. Manufac(cid:173)
`turers of such electronic devices typically supply a remote
`control device along with each electronic device. It is,
`therefore, common for a consumer who has multiple elec(cid:173)
`tronic devices to have multiple remote control devices.
`A remote control device typically controls a selected
`electronic consumer device by transmitting infrared key
`code signals to the selected electronic consumer device. The
`infrared signals contain key codes of a codeset associated
`with the selected electronic consumer device. Each key code
`corresponds 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
`operates an electronic consumer device that is associated
`with a different remote control device, manufacturers some(cid:173)
`times use distinct codesets for the communication between
`various electronic consumer devices and their associated
`remote control devices. The codesets can differ from each
`other not only by the bit patterns assigned to various
`functions of the associated 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
`electronic devices using multiple remote control devices.
`Thus, a 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, 60
`however, thousands of codesets in use in electronic con(cid:173)
`sumer 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
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The accompanying drawings, where like numerals indi(cid:173)
`cate like components, illustrate embodiments of the inven(cid:173)
`tion.
`FIG. 1 is a schematic diagram of a system for relaying key
`65 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.
`
`
`
`US 9,911,325 B2
`
`3
`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(cid:173)
`ments of the invention, examples of which are illustrated in
`the accompanying drawings.
`FIG. 1 is a diagram of a system 10 for relaying a key code
`through a remote control device 11 to an electronic con(cid:173)
`sumer 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, second 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 television 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 35
`on-screen display 15, the type, brand and model of the
`particular electronic consumer device. In this example, the
`user is identifYing 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, sub(cid:173)
`sequent 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
`consumer 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.
`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 keystroke indicator signal16 from a radio frequency (RF)
`transmitter 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 13. In that case, the user presses a "VCR" key
`and then a "power-on" key to cause remote control device 11
`
`4
`to transmit keystroke indicator signal16. Keystroke indica(cid:173)
`tor signal16 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 con(cid:173)
`sumer 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
`10 code comprised of a standardized system code and standard(cid:173)
`ized 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
`15 receiver. The standardized 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 modu(cid:173)
`late the system code and key data to form keystroke indi-
`20 cator signal 16. For example, a microcontroller on remote
`control device 11 uses timing 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
`25 includes a proprietary identification code identifYing the
`pressed key, as well as a proprietary identification code
`corresponding 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
`30 standardized codes that are understood by electronic con(cid:173)
`sumer devices. Remote control device 11 uses any one of a
`number of commonly used modulation techniques to modu(cid:173)
`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
`40 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
`45 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
`commonly used codeset. The key code is comprised of a
`standardized system code and standardized key data. Both
`50 the system code and the key data are digital values. The
`12-bit key code includes a 4-bit system code [0101] and
`8-bit key data [00011100]. In the present example, the key
`code is the key code in the identified codeset that corre(cid:173)
`sponds to the "VCR power-on" key of remote control device
`55 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.
`60 An RF signal for purposes of this patent document is an
`electromagnetic 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
`65 transmitted as a stream of digital values 010100011100,
`where the system code is transmitted first immediately
`followed by the key data without any place holders between
`
`
`
`US 9,911,325 B2
`
`20
`
`5
`them. The standardized system code determined in step 102
`need not identify the brand or model ofVCR 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
`associated 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 communication. 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 communicate 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
`modulated onto key code signal 19 using pulse width
`modulation. 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 25
`intermediary signal. The intermediary signal has an inter(cid:173)
`mediary 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 30
`represents a digital one. The marks and spaces of each pair
`have predetermined lengths. In the embodiment of FIG. 5,
`the 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 35
`space length of a digital one is 2000 microseconds.
`FIG. 6B shows the bursts of the first carrier signal that
`comprise the intermediary signal in more detail. In the
`embodiment of FIG. 5, the bursts that comprise the inter(cid:173)
`mediary signal occur every ten microseconds, resulting in an 40
`intermediary frequency of 100 kilohertz. The duty cycle of
`the intermediary signal is characterized by an "on time" of
`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(cid:173)
`ment of FIG. 5 can also be used. For example, one common
`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" of ten micro sec- 50
`onds and an "off time" of sixteen microseconds. If such an
`intermediary signal were used to generate a 490 microsec(cid:173)
`ond mark 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 55
`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 signal19 in the 60
`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 signal19 and relays the key code communicated by
`first key code signal 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
`
`6
`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 code signal 19 is
`10 converted into key code signal 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 code signal19 and key
`code signal 22, digital ones and digital zeros are modulated
`15 using the same timing for "mark/space" pairs. The wave(cid:173)
`form diagram of key code signal 22 appears the same as the
`waveform diagram shown in FIG. 5 for key code signal19;
`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 signal22. VCR 13 is thereby
`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, charmel 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 user uses the on-screen display 15
`to identifY the type (TV), brand (RCA) and model (Gold) of
`second electronic 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 charmel of television set 14. When
`the user presses the charmel advance key on remote control
`45 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 code set 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 infor(cid:173)
`mation 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 code signals.
`RF transmitter 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
`65 instructed to advance the channel.
`Although remote control device 11 in the first example
`stores either a proprietary codeset or a standardized codeset
`
`
`
`US 9,911,325 B2
`
`7
`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
`inexpensively 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 ZS 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 20
`device 13. In comparison to some conventional systems
`where codesets are downloaded into a universal remote
`control 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 25
`as the on-screen display functionality, data storage capabil(cid:173)
`ity, 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 30
`identified 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 35
`device includes autoscan functionality. Key code generator
`device 12 includes an EMI detector 27 that detects electro(cid:173)
`magnetic 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 gen(cid:173)
`erator device 12 identifies the codeset used to communicate
`with a particular electronic 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 code signals contains a different key code corresponding 50
`to the same desired func