Abstract: An internet-connected service system is provided for facilitating communication across the internet between image-sending and image-receiving systems that have dial-up internet access. The image-sending system, after connecting to the internet, sends a communication request to the service system and the latter is then responsible for waking up the image-receiving system. Upon being woken up, the image-receiving system connects to the internet and contacts the service system. The service system then transfers the current network address of at least one of the systems to the other thereby enabling direct communication to be established between the image-sending and image-receiving systems.

Abstract: A programmable message substitution unit PMSU (60) is provided for modifying signalling messages passing across a link (61) of a telecommunications signalling network without disrupting the link-level procedures operating over the link. In the event of a power failure or upon the detection of an operational anomaly, a bypass relay arrangement (65) is used to bypass the PMSU (60). The PMSU (60) comprises a substitution block for modifying selected messages, a database block for doing database lookups to ascertain new message parameter values to be substituted for existing ones, and a supervision block for checking the operation of the substitution block. The PMSU may be used to implement local number portability or other services.

Abstract: An ATM switch with multicast capability is provided that internally uses input and output identifiers to identify the cell input and output streams, the relevant input identifier being generated for each cell as it arrives. The apparatus has a store for storing both the cell bodies of the cells received by the apparatus and queue data serving to identify in first-in-first-out order, the cell bodies to be output on each output stream. The apparatus is further provided with a send-control subsystem including a scheduling loop and an injection block for injecting output identifiers into the scheduling loop in response to the arrival of new cells. The scheduling loop effects output scheduling of the output streams on the basis of the output identifiers and indicates the next scheduled output stream by outputting the corresponding output identifier, thereby removing it from the scheduling loop.

Abstract: A data recorder includes a recording unit for recording data having a predetermined data format and a frame address in a recording medium in units of frames each consisting of predetermined amount of data, and for forming a plurality of Partitions each consisting of a plurality of data areas in which different types of data are recorded during recording. The data recorder performs initialization of a length of at least one of the Partitions.

Abstract: In this invention, a predetermined amount of data is given as one frame, and data having a predetermined format is recorded for each frame. A first area recording main data and a second area recording sub data are formed in each frame. Plural types of units each consisting of a plurality of frames are set, and a number of first units from a leading end of a recording medium and the numbers of other units from the leading end of the recording medium to a trailing end of the first units are recorded in the second area of a frame constituting the unit including the trailing end, thus facilitating a high-speed search operation.

Abstract: A digital audio tape recorder is used as a digital data storage recorder and digital signals containing main data and sub-data are recorded in separate areas in each track of a plurality of tracks formed on a recording medium, wherein a predetermined number of tracks constitute a group and a plurality of groups are recorded on the medium. In the sub-area an identification signal is further recorded which indicates whether or not main data recorded in the main areas of a given group is same as the main data recorded in the main areas of preceding and subsequent adjacent groups. When identical data is multiply written for a plurality of units, a division of the multiply written portions is detected, and signal processing is facilitated.

Abstract: A method is disclosed for effecting update-in-place of data that has been recorded on tape in oblique tracks using a helical-scan recording technique. The data to be updated is recorded in a block of M tracks lying between first and second continuum each at least of N tracks where N is the worst-case number of tracks required to achieve head/track alignment. The block of M tracks comprises a first series of at least N tracks, a second series of tracks containing the data, and a third series of at least P tracks. When updating the data, the block is rewritten as a whole in a single continuum with the first track of the block being written within a distance of P tracks from the last track of the first continuum.

Abstract: Provided is an apparatus for analysing radio transmission to indicate the condition of a transmission link. The apparatus samples received digital radio signals to produce at each sampling instant a signal or signals representative of the modulation state at that instant. The apparatus includes display means for displaying a given number of the samples as an array of clusters in which each cluster corresponds to one of the modulation states. Associated with the display is a graticule generating means capable of storing data indicative of a plurality of graticule configurations. The apparatus has means which enables the production on the display of a graticule configuration which is appropriate to the cluster array associated with the modulation scheme of the transmission under analysis. In addition there is an adjustment which can be operated to set the relative position of the array and the graticule.

Abstract: The present invention is related to bus extender circuitry for data transmission from a first bus at a first site to a second bus at a second site, includes a first transceiver at the first site, a second transceiver at the second site and a data and control signals transmission medium interconnecting both transceivers. The first transceiver receives data signals and interacts by means of control signals with the first bus which has data and control lines connected to a data source and possibly also to one or more receivers all located at the first site. The second transceiver receives data signals and interacts, by means of control signals, with the first transceiver to transmit data and control signals to the second bus; the second transceiver has data and control lines connected to one or more receivers at the second site.

Abstract: This invention relates to method and apparatus for measuring noise margins in digital transmission systems. The method requires the introduction of a variable pulse into a sequence of pulses which represents normal traffic, varying a parameter of the pulse, detecting the pulse, and accumulating information concerning the variations to determine probability distribution of the deviations produced by measuring the variations relative to a standard. The apparatus includes means for introducing the variable pulse into a sequence of pulses and for observing and recording detection of the variable pulse in each sequence to compile a probability distribution of the aforementioned deviations.

Abstract: This invention relates to slave controlled forward, reverse or third point measurements of at least one of group delay and attenuation distortions of any of a number of transmission sections connected in a measuring loop between a local transmitter and a local receiver. A swept test carrier frequency signal and a fixed reference carrier frequency signal are amplitude modulated by the same modulating frequency and are applied to the transmission section under test in a periodically alternating sequence. After passing through the transmission section under test, the thus generated envelopes of both signals will have suffered a time delay as well as an amplitude degradation caused by the frequency dependent group delay and attenuation characteristics of the transmission section under test.

Abstract: A method and an apparatus for measuring group delay characteristics of a transmission path is disclosed wherein a test signal is fed to the input of the transmission path and the test signal is amplitude modulated by a split frequency. The carrier frequency of the test signal is interchanged periodically between a measuring frequency and a standard reference frequency. The output measuring and reference signals of the transmission path are sensed by noting the positions in time of specified points of the envelope waveform that occur during the periods of the reference type signal and the measurement type signal. A digital pulse counter is provided for measuring a first time interval between a specified point during a period of a first type signal and a specified point during the subsequent period of the second type of signal, and for measuring a second time interval between the latter specified point and a specified point during the subsequent period of the first type of signal.

Abstract: A method for tracking an incrementally sweeping generator by a frequency selective receiver is disclosed. A sequence of test signals is generated each of which has a discrete and different frequency which is periodically and incrementally modified according to a program, and the dwell time of each frequency is sufficient to obtain at least two receiver measurements. This sequence of test signals is supplied to a device under test, and the output signals from the device under test are fed to the frequency selected receiver which operates at one of the discrete frequencies supplied according to the program. The operating frequency of the receiver is modified according to the same sweep program and with at least the same sweep rate. The levels of at least two consecutive measurements at the receiver output are compared with at least one reference value which is selected such that it discriminates against other signals that are not part of the sweep program.