4,099,024
`nu
`United States Patent [19]
`
`
`
`
` Boggs et al. ' [451 Jul. 4, 1978
`
`[54] COMMUNICATIONS NETWORK
`REPEATER
`Invenmm David R_ Bogs!’ Los Altos Hills;
`Robert M_ Manuel Pam Alto, both
`of Cali;-_
`
`[75]
`
`_
`_
`x°"°" C°'1’°"t‘°"' St3mf°'d' Com‘
`[73] Asslgnee‘
`[2]] App]. No.: 769.141
`.
`_
`[22] mod‘
`Feb‘ 16’ 1977
`[51]
`Int. CL? ........................................... .. H041. 25/40
`[52]
`---------------------- 173/71 R
`[53] Field 01' 559-"Sh ------------
`[55]
`References Cited
`
`3
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`:
`
`U'S' PATENT DOCUMENTS
`3,673,326
`5/1972
`Lee
`Primary Examiner—'I'homas A. Robinson
`Attorney. Agent, or Fn-m—Irving Keschner; Barry Paul
`Smith
`
`173/71 R
`
`[571
`
`ABSTRACT
`
`network which includes a plurality of transceivers, the
`repeater being bidirectional and allowing the intercon-
`nectlon of two segmelntslof the network and also allow-
`mg longer communications networks to be used by
`matching or amplifying the signal level of an incoming
`information packet on one segment and coupling the
`matched or amplified signal to a succeeding segment.
`The repeater has two ports that preferably utilize two
`semiconductor chips, each port having a carrier one-
`shot which detects the presence of an information
`packet arriving at that port. If an incoming port's one-
`shot is triggered by an incoming packet of information.
`the carrier one-shot for the repeating port and the in-
`coming port transmitter are disabled. If the transceiver
`coupled to the repeating port detects a coliision, this
`information is fed back to the incoming port which
`enables the incoming port transmitter thereby causing in
`collision on thg incoming ngtwork segment which
`causes the termination of the transmission of the data
`Pack“ by 3 using device aiready transmitting.
`
`A repeater is provided for use in a communications
`
`4 Claims, 2 Drawing Figures
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`TERIIIIMQTOR
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`INTERFNJE
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`int
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`PMC Exhibit 2086
`
`Apple v. PMC
`|PR2016-00755
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`Page 1
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`I
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`TRANSCEIVER
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`PMC Exhibit 2086
`Apple v. PMC
`IPR2016-00755
`Page 1
`
`

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`U. S. Patent
`
`July 4, 1973
`
`Sheetl of2
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`4,099,024
`
`r‘:
`
`TERMIN TOR _
`
`TERM INATOR
`
`TRANSCEIVER
`
` —A
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`PMC Exhibit 2086
`
`Apple v. PMC
`|PR2016-00755
`
`Page 2
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`FIG I
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`INTER FACE
`
`USING
`DEVICE
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`PMC Exhibit 2086
`Apple v. PMC
`IPR2016-00755
`Page 2
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`

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`..lHWaPS.U
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`July 4, 1973
`
`Sheet 2 of2
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`4,099,024
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`PMC Exhibit 2086
`
`Apple v. PMC
`|PR2016-00755
`
`Page 3
`
`PMC Exhibit 2086
`Apple v. PMC
`IPR2016-00755
`Page 3
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`
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`

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`1
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`4,099,024
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`COMMUNICATIONS NETWORK REPEATER
`
`BACKGROUND OF THE INVENTION
`
`A multiaccess communication system without a cen-
`tral control device (_i.e. distributed control) is disclosed
`in copending application Ser. No. 563,741, filed Mar.
`31, 1975 and assigned to the assignee of the present
`invention. The system includes a plurality of transceiv-
`ers connected to the communicating medium utilized in
`the system, each transceiver including transmitting ap-
`paratus for transmitting a signal onto the medium and
`receiving apparatus for receiving a signal onto the me-
`dium and receiving apparatus for receiving a signal
`communicated on the medium by another transceiver.
`Each transceiver includes a collision detector for gener-
`ating a collision signal whenever a signal communicated
`in the medium from another transceiver is received
`during the time the transceiver is transmitting a signal
`onto the medium. the collision signal causing the inter-
`ruption of the transmission of a signal onto the medium
`by the using device connected to the transceiver.
`The network comprises sections of a coaxial cable
`such as disclosed in the copending application or could
`be any suitable medium such as fiber optic cable, radio
`channel or coaxial cable, etc. Since any medium in-
`cludes losses, and since segments thereof may extend
`over large geographic ranges, various losses occur, and
`for that reason sections of the network are tied across
`repeaters.
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`5
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`tor chips, each port having a "carrier” one-shot which
`detects the presence of a packet at that port. If an in-
`coming port’s one-shot
`is triggered by an incoming
`packet of information, the carrier one-shot for the re-
`peating port and the incoming port transmitter are dis-
`abled. If the transceiver coupled to the repeating port
`detects a collision, this information is fed back to the
`incoming port which enables the incoming port trans-
`mitter causing a collision on the incoming segment and
`causing the termination of the transmission of the data
`packet by at using device already transmitting.
`It is an object of the present invention to provide a
`repeater for use in a communications network.
`It is a further object of the present invention to pro-
`vide a bidirectional repeater for use in a communica-
`tions network.
`It is still a further object of the present invention to
`provide a bidirectional repeater for use in a communica-
`tions network wherein the repeater determines the di-
`rection of flow of data without the use of external con-
`trol.
`
`It is a further object of the present invention to pro-
`vide a bidirectional repeater for use in a multiaccess
`communications system without central control.
`It is a further object of the present invention to pro-
`vide a bidirectional repeater which, upon detecting a
`collision at the repeating port, passes the collision back
`onto the incoming port segment of the network causing
`the termination of the transmission of the packet by a
`using device already transmitting.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 shows a portion of the system disclosed in the
`above-identified copending application which requires
`the use of a repeater; and
`FIG. 2 shows schematically the repeater logic of the
`present invention.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Since the present invention is directed to a repeater
`which is particularly adapted for use in a multi-access
`communications system without central control as de-
`scribed in copending application Ser. No. 563,741, filed
`Mar. 31, 1975, the repeater will be described in the
`environment disclosed, including terminology and def-
`nitions utilized therein, in the copending application and
`the teachings therein necessary for an understanding of
`the present invention are incorporated herein by refer-
`CIICE.
`
`As shown in FIG. 1, proximate the intersection of
`cables 10 and 20 (communication medium) there is a
`repeater circuit generally designated by the numeral 50
`communicating on one side between a tap 103 on cable
`II] and a tap 203 on cable 20. On the interior of the
`repeater 50, the cable 10 via tap 103 is tied to a trans-
`ceiver 243, across a repeater logic section 60 to a trans-
`ceiver 245 which then connects to cable 20 by way of a
`tap 203. In this manner, an extended network is formed
`in which two network segments, or cables 10 and 20,
`are tied together across repeater 50 which matches up
`the signals between the cables. It should be noted that in
`addition to matching signals between cables,
`the re-
`peater logic 60 may include amplifying means if the
`selected interconnection points on cables 10 and 20 are
`sufficiently far from the source of a data packet so that
`the data packet input to the transceiver has lost suffi-
`cient strength to require amplification. For the repeater
`PMC Exhibit 2086
`
`Apple v. PMC
`|PR2016-00755
`
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` Page 4
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`Reference to repeaters in the aforementioned applica-
`tion was made for purposes of completing the embodi-
`ment since they are not necessary to practice the inven-
`tion disclosed therein where short communication links
`are contemplated and line losses are taken out by selec-
`tive design of the medium and the transceiver. How-
`ever, in specific applications wherein large communica-
`tion links are contemplated and selective design of the
`medium and transceiver cannot compensate for line
`losses, repeaters generally are required.
`Since the system described in the aforementioned
`copending application is bidirectional
`in nature i.e.,
`there being packets of information flowing in both di-
`rections on the cable which may arrive at the trans-
`ceiver of a using device from either direction. a repeater 45
`for use in such system must be capable of bidirectional
`operation i.e., the repeater preferably will determine in
`which direction to repeat the information packet with-
`out external control. Further, the repeater, which has
`an incoming and repeating part, should be capable of
`responding to the detection of a collision by a trans-
`ceiver at the repeating port and pass the occurrence of
`the collision back onto the incoming segment via the
`incoming port transceiver transmitter and cause the
`using device already transmitting the data packet to
`cease transmission.
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`50
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`SUMMARY OF THE PRESENT INVENTION
`
`The present invention provides a bidirectional re-
`peater for use in a communicating network or medium
`which includes a plurality of transceivers, the repeater
`being bidirectional and allowing the interconnection of
`two segments of the network and also allowing longer
`communicating networks to be used by matching or
`amplifying the signal level of an incoming information
`packet on one segment and coupling the matched or
`amplified signal to a succeeding segment. The repeater
`has two ports that preferably utilize two semi-conduc-
`
`60
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`65
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`PMC Exhibit 2086
`Apple v. PMC
`IPR2016-00755
`Page 4
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`

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`logic described hereinafter with reference to FIG. 2, it
`will be assumed that the transceivers 245 and 243 ac-
`complish the amplification.
`The specific description of the transceivers 243 and
`245 are set forth in the copending application. For pur-
`poses of this disclosure it is sufficient to note that the
`transceiver is capable of receiving an input signal, (data
`paclcet), amplifying it if necessary, transmitting an out-
`put signal (data packet) and generating a signal indicat-
`ing that a data collision (data packets from two different
`sources are being transmitted and received substantially
`simultaneously by the transceiver) has occurred.
`Referring now to FIG. 2. elements 300 and 302 are
`schematic representations of the connections between
`transceivers 243 and 245 respectively, and repeater
`logic 60 and will be referred to hereinafter as the incom-
`ing and repeating ports, respectively. for transmission of
`data packets from left to right as viewed from the fig-
`ure. Obviously, if transmission was in the reverse direc-
`tion. element 300 would act as the repeating port and
`element 302 the incoming port. Incoming port 300 in-
`cludes input data port 304. transmit data port 306 and
`collision signal port 308. while repeater port 302 in-
`cludes input data port 310, transmit data port 312 and
`collision signal port 314. Input data port 304 is con-
`nected to the “A" input of one-shot multivibrator 320
`which may comprise Texas Instruments device SN
`74123. The capacitor 321, resistor 323 and potential
`source Vcc shown are utilized to determine the time
`duration of the active state of the one-shot rnultivibrator
`320 and should be set to about i of the bit times of the
`incoming data if the incoming data is phase encoded as
`set forth in the copending patent application. The Q
`output of multivibrator 320 is coupled to one input of
`NAND gate 326 and to the inverting or “B” input of
`one-shot 360 via leads 330 and 332. respectively. The
`inverted or Q output of one-shot 320 is coupled to one
`input of NAND gate 334 via lead 336. The input data
`packet received at input data port 304 is also applied to
`one input of NAND gate 338 via lead 340. The output
`of NAND gates 326 and 334 are wired “0Red" to-
`gether at point 342 and coupled to the transmit data port
`306. A collision signal applied to the port 308 by trans-
`ceiver 243 is coupled via lead 344 to one input of
`NAND gate 346.
`Referring to the symmetrical right hand portion of
`the schematic diagram, input data received at the input
`data port 310 is coupled to the “A" input of one-shot
`360 via lead 350. the received data packet also being
`coupled to the other input of NAND gate 334 via lead
`352. One-shot multivibrator 360 is identical in configu-
`ration and operation to one-shot rnultivibrator 320. The
`one-shot multivibrators 320 and 360 may comprise
`chips made by Texas Instruments Corporation (TIC)
`Model No. 74123 as set forth lzereinabove and NAND
`gates 334, 326, 338 and 346 may comprise TIC chips
`7438. The Q output of one-shot 360 is coupled to one
`input of NAND gate 346 via lead 364 and the 6 output
`of one-shot 360 is coupled to the other input of NAND
`gate 338 via lead 364. The output of NAND gates 338
`and 346 are wired “ORed” together at point 366 and
`coupled to the transmit data port 312. The output from
`collision signal port 308 is applied to the other input of
`NAND gate 346 via lead 344, the collision signal input
`applied to port 314 by transceiver 245 being applied to
`the other input of NAND gate 326 via lead 368. The Q
`output of one-shot 360 is coupled to the other or "B”
`input of one-shot 320 via lead 370. As indicated, the
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`connectors 300 and 302 (or incoming and repeater
`ports, respectively, in the left to right mode of opera-
`tion) are coupled to respective transceivers (not shown)
`243 and 245 of the type described in the aforementioned
`copending patent application. One-shot multivibrators
`320 and 360 may be referred to as “carrier detectors”
`(an analogy to radio communications) since they moni-
`tor or detect incoming data packets coupled to their
`respective connectors 300 and 302 by transceivers 243
`and 245, respectively.
`In operation, it is assumed that a data packet is being
`repeated from cable 10 via transceiver 243 to repeater
`60 and hence to cable 20 via transceiver 245. If repeater
`60 is going to repeat a signal from cable 10 to cable 20,
`a data packet is received at data port 304 of incoming
`port 300 from transceiver 243 and applied to one input
`of carrier detector 320 and one input of NAND gate 338
`via lead 340, the output of NAND gate 338 being cou-
`pled to transmit data port 312 of repeating port 302 and
`then to transceiver 245. Similarly, if a data packet is to
`be repeated from cable 20 to cable 10, the signal would
`be received by transceiver 245 and applied to one input
`of carrier detector 360 and via NAND gate 334 to trans-
`mit data port 306 and thence to transceiver 243. Since
`both halves of the repeater shown operate essentially
`the same, only the transmission of a data packet from
`transceiver 243 to transceiver 245 will be described in
`detail. The leading bit of a packet (and subsequent bit-
`transitions within the packet) causes the Q output of
`carrier detector 320 to go true (logic “l") and disabl-gs
`carrier detector 360 holding its 6 output true. That Q
`output of carrier detector 360 is applied to one input of
`NAND gate 338 which allows the data packet applied
`to port 304 to be repeated at port 312 (transmit data
`ports use “0" logic to enable the transmit inputs of their
`associated transceivers). Note that carrier detector 360
`must be disabled to prevent it from being triggered by
`the incoming data from transceiver 245 which will be a
`copy of the data being transmitted to that transceiver, a
`characteristic of the particular transceiver design set
`forth in the aforementioned copending patent applica-
`tion. The 3 output of carrier detector 320 will be false
`(logic “0”) and is applied to the input of NAND gate
`334 via lead 336 to disable the transmit data port 306.
`This is necessary because as mentioned above, trans-
`ceiver 245 will be supplying as input data at port 310. a
`copy of the data packet being transmitted at transmit
`port 312.
`If the data packet applied to transmit data port 312 is
`transmitted substantially simultaneously with a data
`packet from some other using device on cable 20, a
`collision is detected by transceiver 245 and a collision
`signal is applied to port 314 and thence to NAND gate
`326 via lead 368. It should be noted that the outputs of
`NAND gates 326 and 334 are joined at point 342 in a
`“wired" DR configuration. Since a logic ‘‘I’‘ input is
`now applied to gate 326 via lead 368 along with the
`logic “I” input on lead 330, NAND gate 326 applies a
`“0" logic signal to transmit data port 306 via wired OR
`342, causing a signal to exist on the transmitter line of
`transceiver 243. A signal
`is therefore transmitted to
`network segment 10 connected to transceiver 243 caus-
`ing a deliberate collision to be created with the using
`device already transmitting on segment 10 and causing
`that using device to terminate its transmission (see the
`description of the transceiver operation in the afore-
`mentioned copending patent application).
`
`PMC Exhibit 2086
`
`Apple v. PMC
`|PR2016-00755
`
`Page 5
`
`PMC Exhibit 2086
`Apple v. PMC
`IPR2016-00755
`Page 5
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`

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`5
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`4,099,024
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`The bidirectional feature of repeater 60 is clearly
`observed from the operation thereof as described here-
`inabove. If a data packet is first received at input data
`port 304. the data packet is repeated at part 312 (Le.
`from left to right as viewed from the drawing). If a data
`packet is first received at input data port 310. the data
`packet is repeated at port 306 (right to left as viewed
`from the drawing}. If a data collision is detected at
`repeating port 314 the transmit data port 306 at incom-
`ing port 300 causes the transceiver coupled thereto to
`create a collision on the connected network whereby
`the using device already transmitting on the network
`terminates transmission. It should be noted that the
`transceiver itself does not cease the transmission when it
`detects a collision, rather, the collision signal causes the
`using device connected to the transceiver to stop send-
`ing bits to the transceiver.
`While the invention has been described with refer-
`ence to its preferred embodiment, it will be understood
`by those skilled in the art that various changes may be
`made and equivalents may be substituted for elements
`thereof not departing from the true spirit and scope of
`the invention. In addition, many modifications may be
`made to adapt a particular situation or material to the
`teaching of the invention without departing from its
`essential teachings.
`What is claimed is:
`
`1. A repeater for use in a data communication system
`of the type comprising a communicating medium, a
`plurality of transceivers connected to the medium, each
`transceiver capable of transmitting data onto the me-
`dium, receiving data communicated on the medium by
`another transceiver, and generating a collision signal
`whenever data communicated on the medium by an-
`other transceiver is received by the transceiver during
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`the time the transceiver is transmitting data onto the
`medium, said repeater comprising:
`a first port connected to a first one of said transceiv-
`ers for receiving data communicated on the me-
`dium and received by said first transceiver;
`a second port connected to said first transceiver for
`receiving collision signals generated by said first
`transceiver;
`a third port connected to a second one of said trans-
`ceivers for applying data and coliision signals to
`said second transceiver for transmission thereby
`onto the medium;
`first means for coupling data from said first port to
`said third port; and
`second means for coupling collision signals from said
`second port to said third port.
`2. The repeater of claim I, further comprising:
`a fourth port connected to said second transceiver for
`receiving data communicated on the medium and
`received by said second transceiver;
`a fifth port connected to said second transceiver for
`receiving collision signals generated by said second
`transceiver;
`a sixth port connected to said first transceiver for
`applying data and collision signats to said first
`transceiver for transmission thereby onto the me-
`dium;
`third means for coupling data from said fourth port to
`said sixth port; and
`fourth means for coupling collision signals from said
`fifth port to said sixth port.
`3. The repeater of claim 2, further comprising means
`for disabling said third means in response to receipt of
`data at said first port.
`4. The repeater of claim 3, further comprising means
`for disabling said first means in response to receipt of
`data at said fourth port.
`3
`I
`I
`$
`It
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`PMC Exhibit 2086
`
`Apple v. PMC
`|PR2016-00755
`
`
`
` Page 6
`
`PMC Exhibit 2086
`Apple v. PMC
`IPR2016-00755
`Page 6