Abstract: Collections of articles or entities are represented on a video display in a manner that allows one to view the relationship, if any, between those articles. One embodiment uses circular representations to model set membership of the entities in one or more of the collections. Another embodiment displays many-to-many and one-to-many relationships between the entities and the collections using two overlapping sets of connective representations with icons displayed at the overlaps to indicate the relationship.

Abstract: A shelf tag printing system includes a portable terminal in radio communication with a base station and a portable printer in wireless communication with the portable terminal. The portable terminal has a bar code scanner which reads product bar codes for radio transmission to the base station. The base station responds with informational signals indicating legends to be printed upon shelf tags by the printer. These signals are received by the portable terminal and relayed to the printer. Communication between the portable terminal and the printer is one-way via a surface wave acoustic resonator in the portable terminal and an amplifier sequenced hybrid receiver in the printer.

Abstract: A shelf tag verifying apparatus having a portable terminal unit in radio communication with a base station and in acoustic wave communication with a nearby bar code reader. The bar code reader reads a bar code printed upon a product which rests upon shelving marked by a tag requiring verification. A decoder mounted within the bar code reader generates a binary product code corresponding to the bar code and appends a check code. A SAWR transmitter then transmits the binary product code and the check code to an ASH receiver mounted in the terminal unit. A microprocessor mounted in the terminal unit verifies the check code and generates a query for radio transmission to the base station, whereupon the base station responds with information for verification of the shelf tag.

Abstract: A dataframe filter is provided a local area network bridge to monitor the dataframes transmitted on one network to determine those dataframes destined to be communicated to another network by the network bridge. The filter receives and examines the destination address of each dataframe communicated on the one filter and, searching through a database maintained by the filter, determine whether the destination address is located on the second network and, if so, signals the bridge to copy the dataframe to the second network.

Abstract: A data stream is received by a first in a series of repeating devices and retransmitted from repeating device to repeating device. As the data stream is retransmitted, the data stream accumulates jitter. A jitter reduction apparatus therefore is used after a series of repeating devices to substantially reduce the accumulated jitter. The jitter reduction apparatus receives the data stream, stores the recognized data, then retransmits the data using a recovered clock signal. According to one embodiment, the recovered clock signal is the clock signal of the original data transmission. According to another embodiment, the recovered clock signal is derived from the data stream as input to the first of the series of repeating devices. Such derived clock signal serves as an estimate of the original data source clock signal. By using a recovered clock signal (e.g.

Abstract: A dataframe filter is provided a local area network bridge to monitor the dataframes transmitted on one network to determine those dataframes destined to be communicated to another network by the network bridge. The filter receives and examines the destination address of each dataframe communicated on the one filter and, searching through a database maintained by the filter, determine whether the destination address is located on the second network and, if so, signals the bridge to copy the dataframe to the second network.

Abstract: Two message security methods and apparatus for the same for token ring local area networks. According to a first method, a port in a ring central controller examines the source and destination addresses of a received data packet and stores a received data packet and replaces the data portion with unrelated data bits only if the address does not match that of the attached user station. In another embodiment, the port scrambles the data portion of the received data packet if the addresses do not match.

Abstract: A security system for local area networks (LAN) to prevent eavesdropping of or to control access to LAN traffic at repeater or concentrator ports. The security system determines which repeater ports are to have security activated according to a given set of criteria. For ports with security activated, the contents of the data field of data frame transmitted from the repeater port to the local device are replaced with an arbitrary bit pattern.

Abstract: A hub network system is provided for communication between nodes. The system can be used, e.g., when one node can be configured for baseband bus topology communication, such as LocalTalk.TM. communication. The node can communicate using the entire bandwidth of the medium, such as 230 Kbps bandwidth, even though other nodes are connected to the network using the hub card. Preferably, the hub card includes a multiprocessor system with a shared memory for providing high internal effective bandwidth communication, such as 15 Mbps communication. A proxy scheme is provided so that the hub topology is transparent to any node which can operate as though it were configured in a bus topology.

Abstract: A security system for local area networks (LAN) to prevent eavesdropping of or to control access to LAN traffic at repeater or concentrator ports. The security system determines which repeater ports are to have security activated according to a given set of criteria. For ports with security activated, the contents of the data field of data frame transmitted from the repeater port to the local device are replaced with an arbitrary bit pattern.

Abstract: A balanced L-section low-pass common mode filter is connected in series with balanced data I/O lines to remove common mode signals from balanced line difference mode signals. The filter includes input and output series transformers configured so that the magnetic fields in the transformers are subtractive for out-of-phase difference mode signals and additive for in-phase common mode signals and a shunt transformer coupled to ground configured so that the magnetic fields in the transformer are additive for out-of-phase difference mode signals and subtractive for in-phase common mode signals. Accordingly, the difference mode signals are not attenuated and common mode signals react to a short circuit to ground and are thereby attenuated by the filter.

Abstract: A balanced T-section low-pass common mode filter is connected in series with balanced data I/O lines to remove common mode signals from balanced line difference mode signals. The filter includes input and output series transformers configured so that the magnetic fields in the transformers are subtractive for out-of-phase difference mode signals and additive for in-phase common mode signals and a shunt transformer coupled to ground configured so that the magnetic fields in the transformer are additive for out-of-phase difference mode signals and subtractive for in-phase common mode signals. Accordingly, the difference mode signals are not attenuated and common mode signals react to a short circuit to ground and are thereby attenuated by the filter.

Abstract: A mandrel (10) of simplified construction and reduced cross sectional size for connection in well tubing comprises a cylindrical body (16) defining a main bore (20) for passage of wire line tools therethrough. A longitudinal slot (30) is formed in the cylindrical body (16). A side pocket subassembly (34, 42, 50, and 52) is secured to the body (16) over the longitudinal slot (30) formed in the body. The slot (30) is sized to permit passage of pocket devices only from the main bore (20) through the offset chamber (44) and into the pocket (60). If desired, an orienting member (22) can be provided within the cylindrical body (16).

Abstract: An apparatus for installing and removing flow valves in a well tubing having a plurality of valve receiving side pockets offset from the main bore by providing an orientation sleeve for directing a guide key of a valve handling apparatus in the sleeve, and a shoulder in the sleeve for actuation of the valve handling apparatus. A valve handling apparatus including a support body supporting a longitudinally movable body which includes a guide key pivotally connected at its lower end and yieldably urged outwardly by spring means so that the guide key will readily pass downwardly through any number of orientation sleeves and can selectively install or remove a valve in or from any desired vertically positioned mandrel.