Abstract: An Adaptive Vector Cancellation method which uses time domain data for an instrument connection to estimate magnitude, phase, and time position of a signal response such as NEXT or Return Loss associated with the connection. Based on the estimate of the amplitude and time of the connection response, a suitable full-bandwidth frequency response that corresponds to a point source of NEXT or Return Loss is determined. This calculated connector response is then scaled to an appropriate magnitude, phase and time shifted to the estimated position of the actual connection. The scaled/shifted response is then vectorially combined with the measured sweep data to suitably cancel the connection contribution to NEXT and/or Return Loss. Thus, the amount of NEXT or return loss existing in the user's patch cord is preserved, while the NEXT or return loss due to the instrument connection is suitably suppressed. Correction is done in the frequency domain, over the full bandwidth of the measured data.

Abstract: The present invention provides methods for using time domain analysis of NEXT, Return Loss and the like, in conjunction with the application of time or distance referenced limits to verify and determine compliance of the performance requirements of connections in a typical link. Time domain analysis of NEXT, Return Loss data and the like, suitably provides the performance characteristics of a link as a function of time or distance. When coupled with time or distance performance curves for connections, it can be determined if the transmission fault is at a connection or in the cable. The time limit curves for connections can be generated based on the frequency domain performance requirements for connecting hardware of a specific level of performance. The connection time limit curves thus provide an interpretation means to determine if the connection is within performance standards, allowing improved isolation of the fault condition.

Abstract: The apparatus includes a first transmitter for transmitting a first test signal from a first end of the cable and a second transmitter for transmitting a second test signal from a second end of the cable. The first test signal is transmitted on a first conductor pair at a first frequency and the second test signal is simultaneously transmitted on a second conductor pair at a second frequency. The apparatus also includes a first receiver for receiving a first coupled signal at the first end of the cable and a second receiver for simultaneously receiving a second coupled signal at the second end of the cable. The first coupled signal exhibits the first frequency and is received on a third conductor pair, while the second coupled signal exhibits the second frequency and is received on a fourth conductor pair. The transmit frequencies are offset such that interference and noise are not detected by the receivers as coupled signals.

Abstract: A computer (10) includes an operating system (14) having a system manager (18) and a native file system (20). An installable file system (36) installs hooks at a core interface (24) between the system manager (18) and the native file system (20). Hooks are installed for only a portion of the many native function routines (26) provided by the native file system (20). A virtual driver (30) communicates with the native file system (20) and simulates a file storage device having substantially no files stored thereon. Foreign file system device (42) requests for function routines that have not been hooked are handled by the native file system (20) and virtual device (30). Foreign file system device (42) requests for hooked function routines are handled by a foreign file system (34).

Abstract: A computer network (10) includes workstations (12), file servers (14), a cabling system (16), and removable media servers (24). Removable media drives (26) couple to the removable media servers (24), and removable media 30 are removably loaded into the drives (26). The file servers (14) may reside in restricted access areas (22), but no such requirement is placed on the removable media servers (24) or their associated drives (26). A workstation 12 originates a request (64) for removable media data (68). The request (64) is redirected (60) from the workstation (12) through the network (10) to a file server (14). A network operating system (NOS) (84) running on the file server (14) passes the request (64) to a removable media redirector (100), which redirects the request (64) back through the network (10) to a removable media server (24). The removable media server (24) obtains the requested data (68) and routes these data back to the requesting file server (14).

Abstract: A microbial transport medium for the collection, transport and storage of samples suspected of having Chlamydia, Mycoplasma, Ureaplasma or viral pathogens comprises a balanced salt solution, a proteinaceous stabilizer, and carbohydrate and amino acid nutrient sources. The medium is buffered to maintain physiological pH and includes a pH indicator in order to maintain pH fluctuation. The medium further comprises antimicrobial and antifungal agents and can comprise gelatin. Samples can be stored in the medium at temperatures ranging from room temperature to minus 70.degree. C. Additionally, the transport medium can be used in standardized commercial ELISA and PCR assays.

Abstract: An instrument to measure crosstalk between conductor pairs is configured to transmit a signal at one pair and receive the signal at another pair. The spureous or parasitic crosstalk at the connectors is supressed using a vectorial substraction from the received signal.

Abstract: Apparatus to measure the crosstalk between pairs of conductors in a cable. The measurements are affected by the crosstalk inherent to the connectors that are part of the apparatus. The improvement consists of adding a compensating signal which equals that from the connector crosstalk in magnitude but has opposite sign.

Abstract: A cable tester, which is adapted to be used by persons not expertly skilled in the technical characteristics of local area networks (LANs), is disclosed. The tester incorporates a time domain reflectometer which starts a counter upon the generation of an incident signal pulse and utilizes a comparator which compares signals present on a cable under test to a controllable amplitude to halt the timer. The tester exhibits an output impedance which is greater than the impedance of a cable being tested. The tester additionally measures instantaneous amplitude levels of signals present on the cable being tested, resistance, continuity, noise levels, and data activity on a network of which the cable is a part. In addition, the tester includes a display and a sound generally device. Software programming compensates for impedance mismatches with the cable and data present on an active network being tested.