WO1988001459A1 - Reseau local d'interconnexion de produits informatique via de longues lignes telephoniques - Google Patents

Reseau local d'interconnexion de produits informatique via de longues lignes telephoniques Download PDF

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Publication number
WO1988001459A1
WO1988001459A1 PCT/US1987/002099 US8702099W WO8801459A1 WO 1988001459 A1 WO1988001459 A1 WO 1988001459A1 US 8702099 W US8702099 W US 8702099W WO 8801459 A1 WO8801459 A1 WO 8801459A1
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WO
WIPO (PCT)
Prior art keywords
network
lan
telephone
local area
area network
Prior art date
Application number
PCT/US1987/002099
Other languages
English (en)
Inventor
Reese M. Jones
Original Assignee
Farallon Computing
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Farallon Computing filed Critical Farallon Computing
Priority to DE1987905986 priority Critical patent/DE289525T1/de
Publication of WO1988001459A1 publication Critical patent/WO1988001459A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks
    • H04L12/403—Bus networks with centralised control, e.g. polling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40—Bus networks

Definitions

  • This invention relates to microcomputer local area networks (LAN's) and modular coupling components thereof and more particularly to a LAN permiting the coupling together of computers and their peripherals through the use of common telephone lines which are unshielded multi-wire cables via modular connectors and jacks.
  • LAN local area networks
  • Interconnect systems for computers and their peripherals require the ability to connect together the computer products to allow each to transfer data such as programs, files, mail, etc., from one machine to the next in a convenient manner.
  • the data transfers are made between different types of computers with the aid of a standard file protocol for the network so that, for instance, a Macintosh ® computer and an IBM ® PC can easily share data given the right software for the network.
  • Apple Computer Inc. had developed its "Apple Talk" (TM) brand network, which allowed several computer products to share expensive or inf requently used peripherals such as modems, printers and mass storage devices. For instance, sharing one laser printer among several microcomputers is one of the most common usages for the AppleTalk connector network.
  • Other uses for the network include electronic mail, sharing or transferring files, sharing mass storage devices and other peripherals.
  • a major problem of state of the art network systems is the perceived necessity to use shielded cable in order to preserve line quality and the quality of the transmission of the data such that breakup or loss of data would be minimized. Without amplification and other sophisticated cabling techniques specialized for each individual situation, it has been recommended that the use of standard flat multi-wire telephone type cable be limited to runs of 25 feet for use in a ground reference (non-differential) circuit.
  • special modules were utilized and special shielded cabling requiring a special plug was thought to be necessary to assure drop-out free transmissions.
  • j umper boxes were required where, for instance, at a given station there was no applicable computer or peripheral.
  • the Apple Talk cabling system is a serial only system which requires sophisticated hardware and a shielded cable, along with shielded connectors in order, it was thought, to transfer error free data from one point to another at a given location.
  • LAN local area network
  • the present invention meets the foregoing object by provision of a LAN modular system which uses for interconnects: in-place telephone wires in conjunction as well as modular telephone connectors which are either already in place or easily installable.
  • a LAN modular system which uses for interconnects: in-place telephone wires in conjunction as well as modular telephone connectors which are either already in place or easily installable.
  • the system of the invention features the production of significant passed-through signal pulses with a superimposed high frequency (relative to the pulse modulation rate of the signal) ringing characteristic at the leading edges of pulse and/or of interpulse dwell ( i.e. , the trailing edge of the pulse) to enable enhanced detectability over long cable lengths notwithstanding degradation of the signal pulses per se.
  • the ringing characteristic is originally produced in the interface transmission units of the computer products, e.g., in accordance with IEEE-RS422 standard.
  • the LAN also comprises surge suppression and static voltage drains on each line so that the floating ground loop defined by the LAN is safe. Runs of up to 5 ,000 feet of cabling permit the system to be utilized throughout an office area without significant degradation of the signals passed between the various modules or units coupled to the line.
  • the LAN of the present invention also permits the use of parallel, T, and Star network topologies as opposed to only daisy-chaining, although daisy-chaining or serial connection is possible without reconfiguring the module or the use of switches.
  • the transformer utilized in the LAN of the present invention is pref errably one having a 50 picofarad or less, and more preferably 10 picofarad or less, interwinding capacitance versus a 360 picofarad interwinding capacitance transformer used in the prior art common ground systems.
  • the transformer is further of an industrial (power) grade with a large inertial mass of its former to constitute a common mode line choke, reducing line conducted interference (LCI) at 10kHz or higher, Phone systems per se operate substantially below this threshhold, typically rolled off at 5kHz or less.
  • the typical computer signals to be imposed on the line have modulation rates of 10 3 - 10 6 baud (pulses per second).
  • the use of only two wires to carry the network signals and wiring to be non-conflicting with the two wires used for telephone tip and ring usage in the telephone cable also permits the network to be run on the typically unused pair of wires in a building's four or more conductor telephone cabling.
  • the telephone and network can each operate undisturbed by utilizing selected pairs of wires within the standard telephone cable.
  • telephone interconnects that were previously made are not affected by the utilization of the other of the pair of wires and the subject module containing the isolation transformer.
  • Termination resistors of 20-200 preferrably 120 ohms are used in the LAN to significantly reduce electrical imbalances between the balanced pair in the phone wires line and reduce reflections at the ends of long runs and avoid phase summing collisions at T and star network connections of the LAN.
  • the foregoing structure has been found to provide a surprising response to the Quad driver-receiver circuits at the computer ends along the network, affording a significant. ringing to maintain raised leading (and trailing) edge corners of pulses to enhance detection sensitivity. Aside fr ⁇ n pre serving this aid to detectability, the LAN of the present invention causes leading edges of pulses of signals passed through it to have an initial slower rise (droop) characteristic thereby further suppressing spurious signal or noise pickup.
  • the combination of the foregoing features affords increased detection reliability over substantially longer length (by orders of magnitude) networks compared to state of the art preceding this invention and enables beneficial use of instal- led public utility and private telephone network wiring.
  • the relative low grade of phone network cabling compared to typical dedicated computer network-wiring is accommodated by the robust network system of the present invention.
  • terminating resistors are utilized by adding them to the first and last wall boxes and at the center of star connections of a large multi-user installation. This is easily done and, as mentioned before, the terminating resistors are 120 ohms which provides exceptionally good matching to standard modular telephone cabling.
  • the utilization of the termination resistor beneficially reduces noise on the network.
  • the local area network of the present invention permits util ization of standard telephone cabling over distances greater by far than previously attained in any volume usage.
  • Running a network without grounds and/or without shielding permits longer cable lengths and the utilization of isolation transformers with less than 10 picofarad interwinding capacitance, rather than the prior art systems' 360 picofarads improves signal response.
  • FIG. 1 is a schematic diagram of the principal elements of a network circuit established in accordance with a preferred embodiment of the invention.
  • FTG. 2 is a qualitatively illustrated pulse modulation waveform produced using the network of FIG. 1 in conjunction with typical, e.g. , quad driver-receiver, circuitry of the computer components attached to the network as shown in FIG. 3; and
  • FIGS. 4 - 6 are diagrams and drawings of phone system inter-relation of the system of FIGS. 1-3, in a mode allowing mechanically convenient interconnection for serial continuity.
  • FIG. 1 there is shown a network according to a preferred embodiment of the invention incorporating a modular subassembly 10 comprising a part 12 of an RJ-11 standard connector connectable to selected pins (2 and 5) of the "wall" portion of a phone system's portion 14 of the connector.
  • the pins "2" and "5" are those leading to wires 2', 5' (i.e., yellow and black, respectively under longestablished U.S./AT&T standards) , which are not part of the essential tip and ring signal wires of the telephone system
  • the subassembly 10 further comprises a cable 20, with leads 22, 24 to a transformer 30 with windings 32, 34 about a high mass metal former 36.
  • a further cable 40 leads to a plug 50 appropriate for the computer or peripheral, e.g., DB-9,
  • the system includes a line termination resistor 16, e.g., 120 ohm, limiting line reflections.
  • the system further includes high impedance (e.g. one Megohm) resistors 26 for draining static voltages and varsitors 28 (zinc oxide resistors, e.g., Panasonic EZR-C05 Dk201) for shorting transient surges to ground and balance resistors 38 as may be appropriate for the interface circuitry attached to plug end 50 as recommended by the manufacturer of such circuitry -- typically IK each to match any of the Am 26LS29-32 Quad Driver/Receivers used in party line configuration producing (and detecting) differential signals from a balanced circuit (e.g., two wire pair) .
  • a balanced circuit e.g., two wire pair
  • the transformer 36 is typically a Coilcraft (TM) P104 -- i.e., a 1.0:1.0 turns ratio transformer with 100 - 1000 turns in each of windings 32, 34 of 20 - 30, gauge wire about an Eform closed loop former of cross-section about equal to a winding loop cross-section, affording a high electromagnetic inertial mass reducing conductive line interference.
  • the interwinding capacitance of the transformer is typically 7pF and the voltage isolation between windings is well over 350 volts, typically 3500 V-RMS, further isolating static charges on the network.
  • the DC resistance of each of windings 32, 34 is under an ohm, preferrably 0.2 ohms maximum.
  • FIG. 2 shows, in portion 2A, a computer generated signal, with some ringing of its own apparent.
  • FIG. 2B shows the down-line signal as detected after passage through two legs (and intermediate phone cabling) of a network as indicated in FIG. 1.
  • leading edge LE there is a slight droop D and slower initial rise (reducing sensitivity to transient noise spikes) .
  • the peak of the leading edge is a pronounced ringing leading to a sharper corner (compared to prior art networks of the class involved here).
  • FIGS. 2C and 2D illustrates degradation of the pulse over a long (e.g. , 1000 feet) cable run without (FIG. 2C) and with (FIG. 2D) the transformer of FIG. 1. Sharpness of leading edge is apparent relative to a reference envelope RE of rectangular form, the y-axis of which is voltage offset, the x-axis being time.
  • FIG. 3 shows party line conf iguration of a single module of the driver-receiver circuit D/R (which is replicated several times, at most three) .
  • FIG. 4 shows schematically the modular system's interconnection via a dual RJ-11 modular connector 12A/12E/14A and single R5-11 modular connector 12C linked via s single isolation transformer 30 to a plug 50 into a computer interface.
  • a further modular connector male plug 14B could couple to 12B to continue a serial chain of computer products or link to a separate phone or PBX network.
  • FIG. 5 illustrates a prototypical network and FIG. 6 is an iscmetric view of the RJ-11 connector.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Dc Digital Transmission (AREA)
  • Small-Scale Networks (AREA)

Abstract

Des interfaces standard d'ordinateurs et de périphériques sont connectées en réseau par des lignes téléphoniques (2', 5') via un réseau local (LAN) comprenant un circuit de terre flottant. Le LAN comprend des unités modulaires d'interconnexion et des prises (50) et des fiches (12, 14) modulaires en combinaison avec un transformateur d'isolation (30) ayant de faibles inerties et capacitances inter-enroulements. Le LAN utilise la caractéristique d'appel superposée sur les bords d'attaque ou de fuite des impulsions de signaux pour améliorer la détectabilité à longue distance et établit une chute de résistance au bruit des bords d'attaque ou de fuite des impulsions. La construction modulaire du LAN permet l'utilisation d'une ligne téléphonique standard à quatre fils, une paire étant utilisée pour le téléphone et l'autre paire étant utilisée pour le réseau. Le réseau peut être connecté dans diverses topologies. Le système LAN permet des interconnexions fiables jusqu'à plus de 5.000 pieds au moyen du câblage téléphonique en place, ce qui permet une réduction substantielle des coûts d'installation ou de modification d'un réseau local.
PCT/US1987/002099 1986-08-22 1987-08-21 Reseau local d'interconnexion de produits informatique via de longues lignes telephoniques WO1988001459A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE1987905986 DE289525T1 (de) 1986-08-22 1987-08-21 Lokales netz zur verbindung von rechnerprodukten ueber lange fernsprechleitungen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US89941386A 1986-08-22 1986-08-22
US899,413 1986-08-22

Publications (1)

Publication Number Publication Date
WO1988001459A1 true WO1988001459A1 (fr) 1988-02-25

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Application Number Title Priority Date Filing Date
PCT/US1987/002099 WO1988001459A1 (fr) 1986-08-22 1987-08-21 Reseau local d'interconnexion de produits informatique via de longues lignes telephoniques

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EP (1) EP0289525A4 (fr)
AU (1) AU7914387A (fr)
WO (1) WO1988001459A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4928303A (en) * 1987-12-29 1990-05-22 Allin Jean Claude Cabling system for low voltage and very low voltage networks in a building
EP0421174A2 (fr) * 1989-09-30 1991-04-10 Franz Leinbach Dispositif de connection pour un réseau local
KR19990073108A (ko) * 1999-05-14 1999-10-05 김명석 유휴전화회선을이용한소규모네트워크구성방법및장치
KR20010019743A (ko) * 1999-08-30 2001-03-15 윤종용 유니버셜 시리얼 버스를 이용한 근거리 네트워크 시스템
US6457434B1 (en) * 2001-02-22 2002-10-01 Rosita de Keersmaeker Wet/dry tissue dispenser

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2523882B2 (ja) * 1989-07-13 1996-08-14 株式会社東芝 デ―タ伝送装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4317205A (en) * 1980-06-13 1982-02-23 Tcl, Inc. Wideband transceiver with EMI suppression
US4689786A (en) * 1985-03-21 1987-08-25 Apple Computer, Inc. Local area network with self assigned address method

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2452207A1 (fr) * 1979-03-20 1980-10-17 Matra Perfectionnements aux dispositifs de couplage d'emetteur sur voie commune et installation de transmission en comportant application
DE3065345D1 (en) * 1979-03-26 1983-11-24 Sperry Corp Passive coupling arrangement and distributed data processing system including such arrangements
JPS5958943A (ja) * 1982-09-28 1984-04-04 Fujitsu Ltd デ−タ伝送システム
US4985892A (en) * 1984-06-01 1991-01-15 Xerox Corporation Baseband local area network using ordinary telephone wiring

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4317205A (en) * 1980-06-13 1982-02-23 Tcl, Inc. Wideband transceiver with EMI suppression
US4689786A (en) * 1985-03-21 1987-08-25 Apple Computer, Inc. Local area network with self assigned address method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0289525A4 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4928303A (en) * 1987-12-29 1990-05-22 Allin Jean Claude Cabling system for low voltage and very low voltage networks in a building
EP0421174A2 (fr) * 1989-09-30 1991-04-10 Franz Leinbach Dispositif de connection pour un réseau local
EP0421174A3 (en) * 1989-09-30 1991-12-27 Franz Leinbach Connecting device for a local area network
KR19990073108A (ko) * 1999-05-14 1999-10-05 김명석 유휴전화회선을이용한소규모네트워크구성방법및장치
KR20010019743A (ko) * 1999-08-30 2001-03-15 윤종용 유니버셜 시리얼 버스를 이용한 근거리 네트워크 시스템
US6457434B1 (en) * 2001-02-22 2002-10-01 Rosita de Keersmaeker Wet/dry tissue dispenser

Also Published As

Publication number Publication date
EP0289525A1 (fr) 1988-11-09
AU7914387A (en) 1988-03-08
EP0289525A4 (fr) 1989-04-24

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