International Business Machines Corporation

Sumitomo Electric Lightwave Corp.

Thomas E Stammely

Kenneth J Christensen

Rudolf Eugene Rehquate

Michael Steven Siegel

Norman Clark Strole

Francis Edward Noel, Jr

Jack S Chorpenning

Eugene J Annunziata

Jerry Dagher

Raymond L Zeisz, Jr

Beymer Bevill, Jr

Max Robert Povse

Kenneth T Wilson

Eugene D Bonnes

Kenneth D Schultz

Keith Quistorff

Jeffrey Matthew Stoltz

James M Faress, Ii

Frances E Noel

A multi-port LAN switch is provided that enables attached network devices to both communicate directly and to insert into a token-ring network through an attached concentrator. Each port of the multi-port LAN switch has a first transformer, a second transformer, and a switching system. The first transformer has a first winding connected to a first connection of the port. The second transformer has a first winding connected to a second connection of the port. The switching system switches to a port mode or an adapter mode as a function of a mode signal transmitted to the port In the adapter mode, the switching system connects a second winding of the first transformer to a transmitter circuit in the port, and its connects a second winding of the second transformer to a receiver circuit in the port. In the port mode, the switching system connects the second winding of the first transformer to the receiver circuit in the port, and it connects the second winding of the second transformer to the transmitter circuit in the port. Each port of the multi-port LAN switch further includes a DC voltage source that is switchably connected to the first connection of the port through a first switch. Each port further includes a second switch that connects the second connection of the port to a DC return-path in a first position, and connects the second connection to the first connection when in a second position.

Multi-port LAN switch for a token-ring network

A fiber optic cable assembly with enhanced flexibility and reduced installation cost in contrast to conventional multiple duct systems. The fiber optic cable assembly comprises a central innerduct adapted to provide a pathway for installing conventional cable by pulling of the cable therethrough. A plurality of air blown fiber (ABF) tubes are positioned around the circumference of the central innerduct for installing air blown optical fiber bundles therethrough, and a plurality of strength elements are provided around the circumference of the central innerduct and interposed among the plurality of air blown fiber (ABF) tubes. A layer of water-blocking material is provided between an outer jacket and the air blown fiber (ABF) tubes and strength members.

Air blown fiber (ABF) tube cable with central innerduct

A multi-port LAN switch is provided that enables attached network devices to both communicate directly and to insert into a token-ring network through an attached concentrator. Each port of the multi-port LAN switch has a first transformer, a second transformer, and a switching system. The first transformer has a first winding connected to a first connection of the port. The second transformer has a first winding connected to a second connection of the port. The switching system switches to a port mode or an adapter mode as a function of a mode signal transmitted to the port. In the adapter mode, the switching system connects a second winding of the first transformer to a transmitter circuit in the port, and its connects a second winding of the second transformer to a receiver circuit in the port. In the port mode, the switching system connects the second winding of the first transformer to the receiver circuit in the port, and it connects the second winding of the second transformer to the transmitter circuit in the port. Each port of the multi-port LAN switch further includes a DC voltage source that is switchably connected to the first connection of the port through a first switch. Each port further includes a second switch that connects the second connection of the port to a DC return-path in a first position, and connects the second connection to the first connection when in a second position.

A device which attaches multiple workstations, printers, computers or the like to a single lobe of a communications network includes a multistation access unit (MAU) with multiple ports and a voltage generator unit which generates a phantom current to activate a remote switch which allows one or more ports on the MAU to transmit or receive information from the communications network.

Data port expander

A method of automatically determining an attached device type for a multi-port LAN switch, and configuring the port based on the attached device type is provided. The method comprises setting a LAN switch port to a port mode, and determining, during a first period of time, whether an attached device is attempting to insert at the LAN switch port. If the attached device is attempting to insert during this first period of time, the method continues by configuring the LAN switch port in the port mode. If the attached device is not attempting to insert during the first period of time, the method continue by setting the LAN switch port in an adapter mode, transmitting a test frame to the attached device, and then determining, during a second period of time, whether a response frame is received from the attached device. If a response frame is received during the second period of time, the method further includes configuring the LAN switch port in the adapter mode.

Method and system of automatically configuring a LAN switch portof a

A ring network of workstations interconnected on a single simplex ring is converted to duplex communications on the single ring by placing two transceivers in each workstation and adding a duplex conversion device between each workstation and its ring terminal box. One of the transceivers receives and retransmits signals in a clockwise direction around the ring; the other transceiver receives and retransmits signals in a counter-clockwise direction around the ring. The clockwise and counter-clockwise signals are superimposed on the ring but are isolated at the workstations by the duplex conversion device.

Full duplex communication on a single communication ring

A station in a communications network determines the mode (full-duplex or half-duplex) in which it communicates with a concentrator port by establishing a Registration routine between the station and the concentrator port. The station and concentrator port exchange frames which disclose the capabilities of the concentrator port. If the concentrator port has duplex capabilities, the station enters as a duplex station. Otherwise, the station enters in a half-duplex (token ring) mode.

Apparatus and method for determining operational mode for a station

A wiring methodology for attaching office machines to a communications network includes at least one central wiring facility or concentrator with lobe segments emanating or fanning out in a 'Star Fashion' configuration to terminal points within offices. A plurality of switch control elements are provided in the concentrator. When activated, each switch control element inserts a lobe segment and attached machines into the communications network. Lobe segments not in use are bypassed (disconnected) within the concentrator. A single station connector (SSC) can be used to increase the number of office machines that may be attached to a single lobe segment. In addition, the SSC may be used to configure a mobile Local Area Network (LAN) System without resorting to permanent wiring schemes.

Local area network station connector

A device, method and system for testing in situ the wiring between a data terminal equipment and a ring or similar type local area network having a loop conduction path with a plurality of data terminal equipment (DTE) coupled to said loop conduction path. The DTE is provided with a mechanism for generating d.c. current. The d.c. currents flow from the DTE through a length of interconnecting conductors and self-shorting connectors towards the loop conduction path. Current measuring devices monitor the current at the interconnecting conductors for imbalance current flow and/or over current. The presence of either a current imbalance and/or over current indicates a malfunctioning (short circuit, broken wire, etc.) in the wiring.

Terminal disconnect and media wire fault detect mechanism

A relay driver circuit, suitable for controlling a bistable relay, includes a storage device which is charged to a first voltage level by a low current flow voltage source. A first switching circuit couples the storage device to the bistable relay when the first voltage level exceeds a predetermined value. The charge on the storage device is dumped into the relay and forces it into a first state (set). A second switching circuit is coupled to sense the voltage on the storage device and the voltage on the low voltage source. When the voltage on the low voltage source falls below the voltage on the storage device, current flows from the storage device and forces the relay into a second state (reset). The reset time is within 100 .mu.s.

Growing community of inventors

Cary, NC, United States of America

Thomas E Stammely