Drop cable for a local area network

• US 4,733,389 A
• Filed: 07/28/1986
• Issued: 03/22/1988
• Est. Priority Date: 07/28/1986
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Puvogel, John M.
• Primary Examiner(s): Olms, Douglas W.
• Application Number:
  US06/890,210
• Time in Patent Office: 603 Days
• Field of Search: 370/5, 370/85, 370/89
• US Class Current: 370/200
• CPC Class Codes: H04L 12/10 Current supply arrangements
• CPC Class Codes: H04L 12/40045 Details regarding the feeding of energy to the node from the bus

Abstract

A multipoint data communication system is disclosed for transmitting data to and from a plurality of communicating devices via an interconnecting cable. This interconnecting drop cable couples a transceiver unit to a communicating device, such as a personal computer, workstation, printer, or the like. The drop cable herein has only two twisted, jointly shielded, pairs of wires to transmit the three signals (transmit, receive, collision) and power. AC differences in the pairs constitute the third, phantom, signal channel. DC differences in the pairs provide the power source for transceiver operations. This cable is considerably less expensive than the industry standard cable.

Claims

1. A multipoint data communication system for transmitting data to and from a plurality of communicating devices via an interconnecting cable, comprising

transceiver means coupled to said interconnecting cable for coupling the interconnecting cable to a communication device and a communicating device to the interconnecting cable,

drop cable means for coupling said transceiver means to said communicating device, and said communicating device to said transceiver means, said drop cable comprising two twisted pairs of wires with an overall shield, and

circuit means at said communicating device for interfacing between said communicating device and said drop cable, wherein three distinct signals and power are conveyed over the two twisted wire pairs in said drop cable utilizing a phantom signal technique of signal transmission,

wherein said transceiver means includes three transformer means for transmitting said three distinct signals, the outputs of one of said transformers being connected to the center taps of the other two transformers, such that a signal introduced by said one transformer is directed to and forwarded by the other two of said transformers, wherein said three distinct signals are alternating current signals while the fourth element is direct current power, and wherein said fourth element representing power is kept separate from said third signal via capacitor means between the output of the other transformer and the center tap of one of said two transformers in both said transceiver means and said circuit means.

2. A multipoint data communication system for transmitting data to and from a plurality of communicating devices via an interconnecting cable, comprising

transceiver means coupled to said interconnecting cable for coupling the interconnecting cable to a communication device and a communicating device to the interconnecting cable,

drop cable means for coupling said transceiver means to said communicating device, and said communicating device to said transceiver means, said drop cable comprising two twisted pairs of wires with an overall shield, and

circuit means at said communicating device for interfacing between said communicating device and said drop cable, wherein three distinct signals and power are conveyed over the two twisted wire pairs in said drop cable utilizing a phantom signal technique of signal transmission,

wherein said transceiver means includes three transformer means for transmitting said three distinct signals, the outputs of one of said transformers being connected to the center taps of the other two transformers, such that a signal introduced by said one transformer is directed to and forwarded by the other two of said transformers, wherein said circuit means at said communicating device includes three transformer means connected together in the same manner as set forth in said transceiver means such that the outputs of one of said transformer means in said circuit means is connected to the center taps of the other two transformers such that a signal received at the center taps of said other two transformers is directed to other transformers to generate said third signal at said other transformers, said third signal being a phantom signal, wherein said three distinct signals are alternating current signals while the fourth element is direct current power, wherein said fourth element representing power is kept separate from said third or phantom signal signal via capacitor means between the output of the other transformer and the center tap of one of said two transformers in both said transceiver means and said circuit means.