United States Patent (19)
`Cotie et al.
`
`11
`45
`
`4,667,193
`Patent Number:
`Date of Patent: May 19, 1987
`
`54)
`
`75
`
`73
`21
`22
`(51)
`52
`58
`
`ADDRESSING SYSTEM FOR
`SIMULTANEOUSLY POLLING PLURAL
`REMOTE STATIONS
`Inventors: Gary R. Cotie, West Chicago;
`Charles H. Culp, Mundelein, both of
`Ill.; Daniel J. Dargis, Knoxville,
`Tenn.; John M. Mendala, Arlington
`Heights; Stephen C. Spielman,
`Glenview, both of Ill.
`Assignee: Honeywell, Inc., Minneapolis, Minn.
`Appl. No.: 561,004
`Filed:
`Dec. 13, 1983
`Int, C.'........................ H04Q 9/00; G05B 23/02
`U.S. C. ........................... 340/825.08; 340/825.54
`Field of Search ...................... 340/825.54, 825.08,
`340/310R, 310A, 870.02, 825.6, 825.16;
`370/96; 455/14, 3
`
`56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`3,522,588 8/1970 Clarke, Jr. et al. ............ 340/825.06
`3,644,894 2/1972 McCrea .......................... 340/825.16
`
`3,702,008 10/1972 Groth. .................................... 370/96
`3,755,781 8/1973 Haas et al..
`340/825.08
`3,755,782 8/1973 Haas et al
`340/825.08
`3,836,888 9/1974 Boenke et al. .......................... 455/3
`3,890,460 6/1975 Haas et al. .......................... 178/2 C
`4,071,908 1/1978 Brophy et al. ...................... 364/900
`4,302,750 1 1/1981 Wadhwani et al............. 340/870.02
`4,586,040 4/1986 Akiba et al. .................... 340/825.08
`Primary Examiner-Donald J. Yusko
`Attorney, Agent, or Firm-Trevor B. Joike; John P.
`Sumner
`ABSTRACT
`57
`In a contention polling arrangement wherein polling
`messages are transmitted by a central controller for
`simultaneously polling a group of remote stations, the
`polling message contains an address which defines the
`entire range of remote stations to be polled and the
`remote stations will respond if their addresses fall be
`tween the address contained in the polling message and
`an address resulting from converting any trailing 0's of
`the address in the polling message to 1's.
`
`21 Claims, 11 Drawing Figures
`
`
`
`CONTROLLER
`
`
`
`
`
`
`
`
`
`
`
`
`
`TRANSPONDER
`
`
`
`CYCLE TIMER
`SBG 8 D
`3A
`Transioner
`CYCLE TIMER
`
`GENERATOR
`
`-3B
`
`TRANSPONDER
`8
`CYCLE TIMER
`SBG8D
`
`
`
`
`
`APPL-1041 / IPR2018-00395
`Apple v. Uniloc / Page 1 of 12
`
`

`

`U.S. Patent May 19, 1987
`
`Sheet 1 of 4
`
`4,667, 193
`
`A/G /
`
`
`
`
`
`
`
`CONTROLLER
`
`MESSAGE
`GENERATOR
`-12
`
`
`
`
`
`
`
`TRANSPONDER
`
`CYCLE TIMER
`SBG 8 D
`3A
`
`TRANSPONDER
`2
`CYCLE TIMER
`SBG 8 D
`3B
`TRANSPONDER
`8
`CYCLE TIMER
`SBG8 D
`3N
`
`
`
`2A
`
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`I7B
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`II/3
`/3
`SAMPLEs->MMMM . . . . . . . . . . . . . . MMMM. .
`
`
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`A/G 4
`
`3.
`
`APPL-1041 / IPR2018-00395
`Apple v. Uniloc / Page 2 of 12
`
`

`

`U.S. Patent May 19, 1987
`
`Sheet 2 of 4
`
`4,667, 193
`
`5
`
`-52
`
`56
`
`57
`
`RECEIVER
`
`N-BIT
`REGISTER
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`DETECTOR
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`STATION -54
`ADDRESS
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`SWITCH
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`
`TO NOR
`GATE 58
`
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`RANGE
`
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`
`82
`
`N-BIT
`REGISTER
`
`PARALLEL TO
`SERAL SHIFT
`REGISTER
`
`
`
`N-BIT
`STATION
`ADDRESS
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`APPL-1041 / IPR2018-00395
`Apple v. Uniloc / Page 3 of 12
`
`

`

`U.S. Patent May 19, 1987
`
`Sheet 3 of4
`
`4,667, 193
`
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`
`CYCLE I
`
`APPL-1041 / IPR2018-00395
`Apple v. Uniloc / Page 4 of 12
`
`

`

`U.S. Patent May 19, 1987
`'U. S. Patent May 19, 1987
`
`Sheet 4 of 4
`
`4,667,193
`
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`APPL-1041 / |PR2018-00395
`
`Apple v. Uniloc/ Page 5 of 12
`
`APPL-1041 / IPR2018-00395
`Apple v. Uniloc / Page 5 of 12
`
`

`

`1.
`
`ADDRESSING SYSTEM FOR SIMULTANEOUSLY
`POLLING PLURAL REMOTE STATIONS
`
`5
`
`O
`
`5
`
`30
`
`BACKGROUND OF THE INVENTION
`The present invention relates to a data communica
`tion system in which a central controller can simulta
`neously poll a plurality of remote stations and can re
`solve any contentions which occur when more than one
`remote station transmit messages in response to the poll
`request. More particularly, the present invention relates
`to a poll request which contains an address portion
`specifying the group of remote stations to be polled
`wherein the address portion is not required to have any
`more bits than are in the addresses identifying the re
`mote stations.
`Computer technologies involving data processing
`and data transmission have been adapted for use in
`building control and supervision because they offer
`20
`advantages and economies which building control sys
`tems had not theretofore achieved. The prior art build
`ing control and supervision systems for maintaining
`comfort control and for monitoring fire and security
`points within the building were not able to easily mini
`25
`mize energy consumption in maintaining desired com
`fort levels nor minimize installation and hardware costs
`in wiring the central control function to the various
`loads being monitored and controlled. Instead of wiring
`the control function to each load separately and instead
`of requiring excessive amounts of hardware to achieve
`energy management functions, the modern building
`control system uses computer technology for connect
`ing the various loads of a building over a single channel
`to the central control function and uses software and/or
`35
`digital technology for achieving energy management
`control.
`In a system comprising a central control station con
`nected over a single communication channel to a plural
`ity of remote stations, each station has a unique address
`and communicates with other stations by transmitting
`digital messages each having an address portion specify
`ing the particular station to which the message is di
`rected. The message will also have other portions, such
`as control and data portions, which may be utilized to
`45
`require the addressed station to perform certain func
`tions such as providing a status report, answer a polling
`message with any alarm messages which it may have to
`transmit to the central controller, requiring a remote
`station to perform a control function such as turning
`50
`loads on or off, as well as requiring a wide variety of
`other functions.
`The polling of remote stations in prior art systems
`was a time comsuming process. The central controller
`polled each of the remote stations one at a time in order
`55
`to receive the desired alarm or status information. Be
`cause such a system was so time consuming, groups of
`stations were polled at one time. In such systems, if
`more than one remote station had information to report
`back to the central controller in response to the poll
`message, the reported messages clashed and the central
`controller received an indecipherable transmission. If
`such garbled messages were received, the central con
`trollers were arranged to enter a contention poll routine
`in which the group to remote stations initially polled
`was subdivided into continuously smaller and/or differ
`ent subgroups until the central controller received only
`clear messages.
`
`4,667, 193
`2
`These prior art contention polling systems have a
`number of drawbacks. Some systems were arranged so
`that each remote station was arranged to respond at a
`predetermined amount of delay after a poll message
`with each remote station having a different delay. Thus,
`contention may not occur until after several remote
`stations have transmitted. The central controller then
`prepared a list of stations which were possibly in con
`tention starting with the first delay period at which
`contention occured and ending with the last station
`which might have transmitted, in view of transmission
`delays, once the controller realized that contention had
`taken place. The central controller was then arranged
`to poll each of the stations individually. This system
`required elaborate timing circuitry at each of the re
`mote stations to generate the required delays and
`rquired complicated processing equipment at the cen
`tral controller for not only recognizing which remote
`stations might be in contention but also for individually
`polling each of the possible contenders once it recog
`nized that contention had occurred.
`In other systems, the central controller simulta
`neously polled a group of stations and if more than one
`response was received and the responses conflicted
`with one another, the central controller conducted a
`poll of some lesser plurality or subgroup of the remote
`stations that were polled previously. The system kept
`subdividing until contending responses were eliminated.
`In these systems, however, the central processor trans
`mitted both an address characterizing the first station of
`the poll and a second address characterizing either the
`extent of the poll or the address of the last station of the
`poll, thus requiring the transmission of two words to
`define the extent of the poll.
`In systems of the nature described above, there has
`been the practice in some cases to transmit the informa
`tion between the various stations of the system over the
`power lines of the building in which the system is lo
`cated. Certain buildings such as large factories may
`require, however, more than one power feed into the
`building. It has been the practice in the prior art to
`connect the central controller to a master modem for
`communication with one of the power feeds and to
`interconnect the other power feeds by the use of repeat
`ers. The use of a master modem with a plurality of
`repeaters depending on the number-of power feeds
`makes isolation of the power feeds from one another
`more difficult and does not allow for the kind of flexibil
`ity which is required for systems of this type.
`SUMMARY OF THE INVENTION
`Accordingly, the present invention involves a system
`for polling a plurality of remote stations at one time and
`for resolving contentions which may occur when two
`or more remote stations report by continuously subdi
`viding the group of remote stations into smaller and/or
`different subgroups until contentions are eliminated.
`The poll message contains an address portion of only
`one word duration which defines by itself the group of
`remote stations to be polled. Thus, the present invention
`is directed to a data transmission system having a cen
`tral controller for transmitting polling messages, a com
`munication channel connected to the central controller,
`and a plurality of remote control modules connected to
`the communication channel for receiving the polling
`messages, the polling messages having an address por
`tion therein, and each remote control module having
`the capability of recognizing any trailing "zeros' in the
`
`60
`
`65
`
`APPL-1041 / IPR2018-00395
`Apple v. Uniloc / Page 6 of 12
`
`

`

`5
`
`40
`
`50
`
`20
`
`4,667, 193
`4
`3
`messages transmitted between controller 11 and its re
`end of the address message and determining if its own
`mote stations.
`address is included within the address contained in the
`By way of example only, controller 11 can be con
`polling message and an address which results from con
`nected to a plurality of transponders 14A, 14B and so on
`verting the trailing "zeros' of the address in the polling
`through 14N, with N in this particular example being
`message to "ones'.
`selected as the number 8. Thus, eight transponders can
`Another aspect of the invention is a system involving
`a plurality of transponders, one transponder for each
`be connected to controller 11. In this particular exam
`ple, the system is designed to accommodate up to eight
`power feed into the building for interconnecting its
`transponders so that each transponder can channel mes
`associated power feed with the central controller. Each
`transponder is microprocessor based and functions to
`sages between controller 11 and the associated remote
`10
`stations over a corresponding power feed through a
`receive and transmit messages between the central con
`building. The system shown in FIG. 1 can handle up to
`troller and the remote control modules to which it is
`eight power feeds to a building. If the building has only
`connected. Also, when the transponder receives mes
`one power feed, then only one transponder is needed.
`sages from its remote control modules to pass on to the
`central controller during a polling operation, it will
`The connection between controller 11 and transpon
`15
`report that information back to the central controller if
`ders 14 can, by way of example, be conducted over a 20
`no transponder having higher priority has responded
`milliamp current loop.
`but will reset its registers if a transponder having higher
`Transponder A is then connected over the power
`priority has responded.
`lines in a power feed system to remote control stations
`or modules 15A, 16A, 17A and so on. Each of the other
`BRIEF DESCRIPTION OF THE DRAWINGS
`transponders is also connected by its respective power
`These and other features and advantages will become
`line system to a number of remote control modules as
`more apparent from a detailed consideration of the
`shown in FIG. 1.
`invention when taken in conjunction with the drawings
`Each transponder has a cycle timer portion 18 the
`25
`in which:
`function of which will be described hereinafter in con
`FIG. 1 shows a circuit schematic of the data process
`nection with FIG. 9. Each transponder also has a start
`ing system according to the present invention;
`bit generation and detection portion 13 so that the asso
`FIG. 2 shows a message which can be transmitted
`ciated transponder 14 in transmitting messages to the
`between the controller and the remote control modules
`remote control module means can provide a start bit to
`of FIG. 1, the message having a start bit portion B;
`30
`be recognized by the remote control modules and can
`FIG. 3 shows the start bit portion B of the message in
`detect start bits of messages initiated by the remote
`FIG. 2 in more detail;
`control modules. Similar to transponders 14A-14N,
`FIG. 4 shows an arrangement wherein the micro
`each remote control module has a message generating
`processor of either the transponder or the remote con
`portion 19, 20, 21 and so on for generating messages and
`trol module can sample the bits received to distinguish
`35
`for providing start bit generation and detection.
`a start bit from a data bit;
`Controller 11, transponders 14 and remote control
`FIG. 5 shows a functional diagram wherein a station
`modules 15-17 can each contain a microcomputer for
`can determine if its address falls within the range de
`more easily performing the control functions necessary
`fined by the address contained in a polling message;
`to such a system. The transponder microcomputer can
`FIG. 6 shows the trailing "zero' detector of FIG. 5 in
`be arranged to control both the current loop receive
`more detail;
`and transmit function between controller 11 and the
`FIG. 7 shows an alternative arrangement for deter
`transponder, and the power line carrier receive and
`mining whether a station address falls within the range
`transmit function between the transponder and the re
`established by the address contained in the polling mes
`mote control modules connected to it over its associated
`45
`Sage;
`power line, as well as error detection and any desired
`FIG. 8 shows an operation in which the transponder
`housekeeping information functions. The remote con
`shown in FIG. 2 can convey messages from the remote
`trol module microcomputer controls power line carrier
`control modules to the controller to resolve contentions
`receive and transmit functions, performs error detec
`between various transponders; and,
`tion, and controls analog and digital input sensing and
`FIGS. 9A-9C show one of the transponders in FIG.
`output control as well as any desired housekeeping
`1 in more detail.
`functions.
`DETAILED DESCRIPTION
`Such systems are familiar in the arts and need not be
`elaborated on here except to show the particular mes
`The system shown in FIG. 1 is particularly useful
`sage construction which is provided by the apparatus
`when the communication channel is selected to be
`55
`shown in FIG. 1 and to explain how the start bit in the
`power line carriers within a building although it is to be
`message can be distinguished from data bits.
`understood that the present invention may be used on
`The message which can be transmitted between the
`systems other than power line carrier systems. The
`transponders and remote control modules may take the
`system comprises central controller 11 which directs
`form shown in FIG. 2. This message may have a portion
`the control and supervisory functions of a plurality of
`60
`'A' which is simply a portion for conditioning the
`remote stations. Such functions can include energy
`transmission line and which may have a duration of 1 bit
`management functions for controlling a building's air
`time.
`conditioning plant to establish and maintain the envi
`Portion "B" is a start bit to inform receiving stations
`ronmental conditions within a building at comfortable
`that a data transmission is beginning. For purposes of
`levels as well as alarm functions such as may involve the
`the present invention, a start bit is defined as either a
`monitoring of fire and security points around the build
`single bit or a multiple bit sequence used to define the
`ing. Controller 11, as is typical in systems of this nature,
`contains a message generation portion 12 for generating
`start of a data transmission.
`
`65
`
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`Apple v. Uniloc / Page 7 of 12
`
`

`

`4,667, 193
`5
`6
`Portion "C" is a direction bit, which may be only 1
`further limited by circuit 37 and connected to circuit 38
`bit in length, for indicating the direction of the message.
`which provides active filtering at the mixed down fre
`One remote station, depending upon system configura
`quency-shift-keying frequencies chosen for transmis
`tion, need not read messages which are being transmit
`sion. The signal is then connected back from device 38
`to device 37 for detection and is then supplied to micro
`ted from another remote station to the central control
`ler 11. Bit C can perform this function.
`processor 39. One output of circuit 37 is connected to
`the interrupt terminal of processor 39 and the other
`Portion "D' contains a function code and can include
`7 bit times for indicating the particular function of the
`output from device 37 is connected to the data input
`message. The message could be a poll message, a con
`terminal of device 39.
`trol message, a status report message, an information
`As shown in FIG. 3, microprocessor 39 repetitively
`10
`message or the like.
`samples the information at its interrupt terminal. Micro
`Portion "E" is an address portion which may be 8bits
`processor 39, because of this multiple sampling, can
`in duration defining the address to which a particular
`then distinguish a start bit such as that shown in FIG. 3
`message is directed.
`from normal data bits. Since the start bit bears a frac
`Portion "F" is a point number field. This portion is
`tional relationship to data bits, it will not be confused
`used for transmissions from controller 11 to remote
`between the start bit and a data bit.
`When controller 11 requests a group poll of remote
`control modules and contains a number of bits to define
`the specific point controlled or supervised by a remote
`stations, it issues a message similar to that shown in
`control module which is to perform some function as
`FIG. 2. In this case, the function code portion "D” will
`directed by the controller 11.
`indicate a group poll and address portion "E" will con
`20
`Finally, portion "G" is a multibit cyclic redundancy
`tain an address defining the addresses of the remote
`character error checking portion.
`stations in the group. In the specific example shown, an
`address unique to the remote station is stored in each
`The start bit is shown in more detail in FIG. 3. At
`least a portion of the start bit has a duration which is of
`remote station. This address is comprised of N bits
`a different length in terms of time from a data bit. The
`which may in this example be 8 bits. Address field E
`25
`start bit can be a single bit, i.e. a continuous signal level
`also contains 8 bits. If there are trailing 0's, that is the
`bounded by two opposite signal transitions, having a
`contiguous 0's which occupy the lesser significant bits
`duration which is fractionally rather than integrally
`of the address portion in field "E" starting with the least
`related to a data bit. For example, the start bit may be a
`significant bit, then the group being polled is defined as
`zero having a length which is , , 4/3 or the like of a
`a range of addresses starting with the address in field
`30
`data bit. Accordingly, the start bit may have a duration
`"E' and ending with an address determined by chang
`which is n/m again as long as a data bit where m) nor
`ing all trailing 0's to 1's. In this way, a single word can
`m Cn but not m=n. Thus, the receiving station can
`define the entire range of addresses within the poll.
`As examples, if the address in the polling message
`measure the length of time of the bits received and
`determine when a start bit is received and can then
`contains all 0's, then the low end of the range is as de
`35
`distinguish that start bit from data bits.
`fined by the address, i.e. 00000000, and the high end is
`defined by changing all trailing 0's in the received ad
`However, an extra level of protection can be obtained
`from the particular example shown in FIG. 3, wherein
`dress to 1, i.e. 11111111. If the received address is
`the start bit is in actuality a sequence of three individual
`01.000000, then the range is defined on the low end by
`bits because this bit pattern can be more easily discern
`01000000 and at the high end by 01111111. As a third
`ible by the receiving station. The first and third individ
`example, if the received address is 10110111, then the
`ual bits have a length which is 1 as long as a data bit
`range is defined on the low end by 10110111 (the re
`ceived address) and at the high end by 10110111 (since
`and a second intermediate bit which is of the same
`length as a data bit. The overall bit is therefore 3 the
`there are no trailing "O's').
`Although this function may desirably be performed
`length of a normal data bit.
`In prior art systems, receivers typically recognize bits
`by the microcomputers in the remote control modules,
`by sampling in the middle of a bit time to determine
`FIG. 5 shows a functional block diagram of how a
`remote station can recognize whether its address is
`whether it has received a 0 or a 1. In the case of the start
`within the range of addresses relating to the group of
`bit shown in FIG. 3, such a prior art system will not be
`able to distinguish between a bit which has a fractional
`stations or modules being polled.
`50
`relationship to a data bit. Accordingly, multiple samples
`The incoming message is received by receiver 51 of
`of incoming bits must be taken in order to determine
`FIG. 5. The address is then shifted into an N bit register
`whether this fractional relationship has occurred. As
`where N stands for the number of bits in the address.
`shown in FIG. 3, the multiple samples will indicate that
`Each station has a unique address, also comprised of N
`the start bit does bear a fractional relationship to a data
`bits. EXCLUSIVE OR 53 then compares the received
`address stored in N bit register 52 with the N bit station
`bit.
`.
`address stored in register 54, the result of the compari
`FIG. 4 shows a circuit apparatus which can be used at
`both the transponder and at the remote control modules
`son being stored in EXCLUSIVE OR output register
`55. Also, the parallel information stored in N bit register
`for start bit detection. The terminals 31 are connected to
`the power line to which the particular station is associ
`52 is connected to trailing "zero' detector 56 which
`ated and a filtering section 32 is provided for filtering
`detects any trailing zeros and clears the corresponding
`out the 60 cycle power line current. Only system mes
`bit positions in register 55 by use of a clear zero switch
`sages should be present past the filter section 32. Clip
`57. The output from switch 57 is then connected as
`ping diodes 33 are provided for clamping the received
`inputs to NOR gate 58 which will provide a "1" output
`signal and step-up transformer 34 is provided for band
`only if all inputs are "0".
`65
`pass filtering. Additional diodes 35 are provided for
`Thus, the EXCLUSIVE OR operation will compare
`additional limiting with the received signal being sup
`the received address with the stored address bit by bit.
`plied to mixer 36. The mixed signal is amplified and
`Because of the EXCLUSIVE OR operation, for each
`
`45
`
`5
`
`55
`
`APPL-1041 / IPR2018-00395
`Apple v. Uniloc / Page 8 of 12
`
`

`

`5
`
`10
`
`15
`
`4,667, 193
`8
`7
`match. Since not all bit positions contain 0's, there is no
`bit position in which register 52 and register 54 contain
`match.
`the same bit value, EXCLUSIVE OR gate 53 will pro
`FIG. 7 shows an alternative method for determining
`vide a “0”. EXCLUSIVE OR gate 53 will only provide
`whether a station address is between the address re
`a "1" for those bit positions which have different bit
`ceived and an address resulting from converting any
`values stored in register 52 and register 54. If trailing
`and all trailing "O's" of the received address to "1's'.
`“0” detector clears those "1's' stored in register 55
`The functional alternative represented by the circuit of
`corresponding to the trailing "O' bit positions of the
`FIG. 7 takes any trailing "O's" in the received addresses
`address stored in register 52 and if only "O's" remain,
`and shifts them into that end of the EXCLUSIVE OR
`the circuit of FIG. 5 has determined that the address
`register having the most significant bit. In this manner,
`stored in register 54 is within the range identified by the
`the number of least significant bits shifted out of the
`address stored in register 52. In this way, the functional
`EXCLUSIVE OR register will be the same as the num
`apparatus shown in FIG. 5 determines whether the
`ber of trailing "O's".
`station address stored in register 54 is included within a
`Thus, as shown in FIG. 7, the received address is
`range of addresses beginning with the address received
`recieved in receier 81 and stored in N bit register 82.
`in register 52 and ending with an address resulting from
`EXCLUSIVE OR gate 83 compares this received ad
`changing the trailing "O's" of the address stored in regis
`dress with the stored address in register 84 with the
`ter 52 to "1's'.
`output of the comparison being stored in EXCLUSIVE
`FIG. 6 shows functionally how the trailing "O' detec
`OR register 85. Then, a parallel to serial shift register 86
`tor 56 can operate. The outputs of registers 55 are con
`will shift the trailing "O's" stored in register 82 into
`nected to individual switches 61, 62, 63 to 6.N. The least
`20
`register 85. The outputs of register 85 are then con
`significant bit in the address stored in register 52 is
`nected as inputs to NOR gate 86 with a result similar to
`connected directly to control switch 61. If this bit value
`the apparatus shown in FIGS. 5 and 6.
`is a "0", switch 61 will supply a "0" output to NOR gate
`As an example of this operation, if the poll address is
`58 regardless of the value of the corresponding bit posi
`11011000 and the station address is 11011100, the EX
`tion from register 55. The least significant bit output
`25
`CLUSIVE OR is performed to obtain 00000100. The
`from register 52 is “OR'ed by OR gate 72 with the next
`first trailing zero is shifted into this result to obtain
`least significant bit and the output of OR gate 72 con
`00000010, the next to obtain 00000001, and the third to
`trols switch 62. If the two least significant bits from
`obtain 0000000. Since all positions are "0", there is a
`register 52 are both "O's", then the output from OR gate
`match.
`72 is also a "0" and switch 62 insures a “0” output to
`30
`As another example, if the poll address is 11011010
`NOR gate 58 regardless of the value of the correspond
`and the station address is 11011100, the EXCLUSIVE
`ing bit position in register 55. As can be seen from FIG.
`OR is performed to obtain 00000110. Since there is only
`6, if any bit position in register 52 has a "1" output, its
`one trailing "0" in the poll address, only one "0" is
`associated OR gate and all higher OR gates will have a
`shifted into the EXCLUSIVE OR result yielding
`"1" output operating the corresponding switches to
`00000011. Because not all bit positions contain a "0",
`connect the corresponding outputs of register 55 to
`NOR gate 58 will indicate that the station address is
`NOR gate 58. In this way, the bit positions in register 55
`outside of the poll addresses.
`corresponding to the trailing "O' positions stored in
`Since the system shown in FIG. 1 can handle up to 8
`register 52 will be cleared with the remainder of the
`transponders, more than one transponder can receive a
`outputs from register 55 being connected to the input of
`40
`message from their associated remote control modules
`NOR gate 58 as is. If any of these outputs have a "1",
`because either alarms can occur on more than one
`then there is no match between the address received
`power feed at the same time or, since transformers vary
`and the station address and, thus, the station will not
`in the isolation at the particular frequencies used for
`respond to the poll.
`transmission, an alarm message sent on one power feed
`Switches 61-6N can be two position switches. In the
`potentially can be detected by both the transponder on
`first position, the corresponding input to NOR gate 58 is
`the power feed on which the alarm originated and a
`connected to ground; this position results from a zero
`transponder on another power feed because of the poor
`int to the switch. In the other position, the corrsponding
`isolation. The present system provides a slotted conten
`input to NOR gate 58 is connected to its associated
`tion arrangement for allowing plural transponders
`output from register 55; this position results from a one
`which have messages to report to communicate with
`input to the switch.
`As an example of this operation, if a poll address of
`the controller.
`In this system, the transponder having the highest
`11011000 is received by a remote station having an
`priority is given the lowest number and the transponder
`address of 11011100, an EXCLUSIVE OR is performed
`having the lowest priority is given the highest number
`to obtain 00000100. The “1” in this result is supplied as
`with the remaining transponders prioritized therebe
`an input to switch 63. However, since there are three
`contiguous trailing "O's", the OR gates 72 and 73 pro
`tWeen.
`When the transponders receive a message from the
`vide "0" outputs so that the control inputs to switches
`controller, they transmit that message on their respec
`61-63 are all '0'. Thus, the “1” input to switch 63 is
`tive power feeds simultaneously. At the time each tran
`cleared and NOR gate 58 has all “0” inputs determining
`60
`sponder finishes this retransmission, it sets a timer 18.
`that the address of the remote device falls within the
`This timer controls the time when the transponder may
`specified range. As another example, if the address in
`respond to the controller. The transponder having the
`the polling message is 11011010 and the remote device
`highest priority is set to respond first, the transponder
`has an address of 11011100, the EXCLUSIVE OR op
`with the next highest priority is set to respond a short
`eration results in 00000110. Since there is only one trail
`65
`time delay after the transponder having the highest
`ing 0 in the address received, the last bit position of the
`priority and so on with the transponder having the
`EXCLUSIVE OR register is cleared and the remaining
`lowest priority set to respond last after the most time
`bit positions are used to determine whether there is a
`
`45
`
`35
`
`50
`
`55
`
`APPL-1041 / IPR2018-00395
`Apple v. Uniloc / Page 9 of 12
`
`

`

`4,667, 193
`10
`delay. If any transponder responds during its time slot,
`When the transponder is receiving over the power
`the remaining transponders detect that transmission to
`lines, LED 111 will be flashed at pin P14 of micro
`the controller. When one message is sent to the control
`processor 101 to provide a visual indication of this
`ler,