Abstract: Apparatus for determining the position of a cursor with respect to a floating coordinate system, such as a menu. The floating menu incorporates two sensing devices similar to that in the cursor. A processing unit determines the position of the two sensing devices and the position of the cursor with respect to a fixed coordinate system. From this data the position of the cursor with respect to the floating menu is determined.

Abstract: A transparent intelligent communication network having both terrestrial and satellite links between nodes and providing improved accuracy and speed in transmission by distinguishing between data requiring rapid receipt at the receiving node and other data, and dispatching data accordingly, while transmitting system protocol and error-correcting information (e.g., retransmissions) over terrestrial links.

Abstract: A system is disclosed for utilizing command buffers in a microprocessor controlled electronic code keyer for storing, rather than text to be transmitted, command strings for keyer operation. The command string is defined by a series of keypad closures for selecting a sequence of text buffers to be transmitted. In addition, the command buffers may be used during automatic text transmission to selectively change keyer parameters such as the speed of character transmission, inter-character and inter-word spacing, dot-to-dash-to-space ratio, or the number of times the contents of a text buffer will be automatically repeated. The use of text and command buffers permits the formation of essentially errorless Morse code transmissions, substantially enhances keyer operating and makes more efficient use of available memory.

Abstract: A modular telecommunication system comprises switching blocks interconnected by bus-oriented interconnecting lines. Each switching block includes line terminators each adapted to be connected to a respective data terminal and control means for controlling local data exchange between line terminators directly connected thereto and remote data exchange from local line terminators to a data terminal associated with a different switching block. The interconnecting lines include a plurality of individually controlled interlink buses, which are coupled to each switching block by a separate interlink-bus interface unit and a short distance transmission line. Data transfer across an interlink bus is performed under control of an interlink-bus controller associated with each bus, by scanning the interlink-bus interface units. Data characters are transmitted in time-multiplex mode together with address information of the receiving switching block for selecting the receiving interlink-bus interface unit.

Abstract: A modular telecommunication system comprises a plurality of switching blocks and a plurality of inter-connecting lines for interconnecting the switching blocks. Each of the switching blocks includes a multiplicity of line terminators each adapted to be connected to a respective data terminal. A communications controller is provided in each switching block for controlling local data exchange between pairs of line terminators connected thereto across real channels. A virtual channel controller is connected to the communications controller and controls remote data exchange across virtual channels to different switching blocks. Interface units are arranged between the virtual channel controller and a respective one of the inter-connecting lines for providing remote data exchange between data terminals each associated with a different switching block.

Abstract: A system is shown for automatically detecting the integrity of telephone subscriber's line connection to a four wire switching system via a hybrid network.

Abstract: A muldem (100) has a monitor (101) for testing data path failures through the muldem (100) by comparing the latter's input and output. The monitor (101) includes comparing means (806, FIGS. 13a and b) with a data comparator (880, FIGS. 13b and 17) for bit error detection by comparision of a pair of data streams (A+B) processed through the monitor (101) from the input and output of the muldem (100). The data comparator (880) delays one of the data streams (A) by a fixed amount and variably delays the other data stream (B), and then slipshifts the data streams in time until they are in alignment to be compared. The data comparator (880) detects noncoincidences of bits in the two data streams and counts such errors over a given sampling interval, providing a bit error rate. If this rate is above a user selectable threshold, then a malfunction in the tested data path is probable, so the path is retested, using a longer sampling interval, to improve the statistical accuracy of the test.

Abstract: A dialing system which utilizes a keypad on teleprinters retrofitted into existing teleprinter models through interfacing by voltage biasing and output circuitry with integrated circuit components having inputs to the teleprinter keypad and a pulse driver coupled to the existing dialing circuit through relays. The relays, driver and integrated circuit components are energized under different voltage levels lower than the teleprinter operating voltage through the voltage biasing circuits connected to the teleprinter power supply.

Abstract: An electronic d.c. telegraph transmitter comprises a transmitting keying circuit and a current regulating circuit which operates in accordance with the principle of a continuous regulator and serves to maintain the line current constant. The power loss which is converted into heat is as small as possible. Between the current regulating circuit and the telegraph battery, a switching stage connects only one tap of the telegraph battery to the input of the current regulating circuit. The voltage present at the input of the current regulating circuit is automatically increased or reduced in stepped fashion in dependence upon the transmitting voltage which occurs on the transmission line.

Abstract: A muldem (100) has a monitor (101) for testing data path failures and standby data protective switching means (108, 109) providing alternate standby data paths in the event of a malfunction. The system accepts a maximum of fifty-six standard low speed T1 lines (1.544 Mb/s), fourteen standard intermediate speedT2 lines (6.312 Mb/s), or any combination of T1 and T2 lines to generate two standard high speed T3 lines (44.736 Mb/s). The structure allows for partial equipping of low and intermediate speed circuits by accepting any number of circuits up to the maximum capacity of the high speed circuits. The system provides automated adjustment for expansion and contraction of the system while in operation. Individual T1 and T2 signal paths may be added or removed with no disturbance to any other path. The monitor automatically adjusts to test data paths through added T1 or T2 circuits and to ignore data paths through removed T1 or T2 circuits.

Abstract: An electronic transmitter for direct current telegraphy systems. In order to limit cross-talk between neighboring telegraph lines it is known to filter telegraph signals prior to transmission to "round-off" their edges. In the present electronic transmitter telegraph signals are given approximately "sinusoidal edges" by the use of a function generator. In FIG. 1 an electronic transmitter comprises an input circuit 1, a switching circuit 2 and an output circuit 3. Binary information signals at an input produce telegraph signals on a telegraph line 6-6'. The output circuit 3 comprises two function generators 15 and 17 and a current source 21. Switches 11 and 14 in the switching circuit 2 control which function generator is operative in response to command signals D.sub.1 and D.sub.2 from the input circuit. The result is that current pulses from the current source 21 have exponentially varying leading and trailing edges which approximate the sinusoidal edges as shown in FIG. 2.

Abstract: The circuit arrangement monitors operating conditions of consecutively sampled direct current devices. The operating conditions are represented by different potentials occurring at a sampling connector of each different direct current device. A selector unit has parallel signal inputs, each of which inputs is connected to a respective sampling point of a DC device. A comparator is coupled by a first input to a reference voltage source and by a second input to the output of the selector unit. An output of the comparator is connected to a shift register buffering the output signals of the comparator for one monitoring cycle. The selector unit and the shift register are commonly controlled for synchronous selecting operation and shifting, respectively. There is arranged a feedback network between the output of the shift register and the first input of the comparator for superposing a positive feedback signal on the reference voltage.

Abstract: A synchro transmitter having a rotor driven by a compass communicates the heading information from that compass to a plurality of loads via respective synchro receivers whose rotors are energized with direct current or carry permanent magnets and whose stators are supplied with a triad of d-c signals from three modular units each having one input connected to an output lead of a respective stator winding of the transmitter and another input connected in parallel with a winding on the transmitter rotor to a source of alternating current. A demodulator in each unit compares the current of the respective output lead with the reference current from the a-c source and feeds the result to an integrating operational amplifier which emits the corresponding d-c signal.

Abstract: An apparatus for measuring phase and amplitude jitter and simultaneously and audibly counting and monitoring transient excursions of two linear bar-chart type readouts calibrated in degrees and modulation percents and which are capable of displaying jitter measurements. The transient excursions in the form of phase hits, gain hits, drop outs and impulse noise are simultaneously counted in parallel registers and means are provided for visually indicating the cumulative real time count total of each register in numerical display. The method of evaluating parameters affecting voiceband data transmission includes simultaneously displaying phase and amplitude jitter components onto linear bar-chart displays and separately deriving the information for each of said displays and providing continuous and sequential illumination on each display encompassing the range of fluctuations from the jitter detectors.

Abstract: This invention relates to improvements in the functional design of electrical key-like devices and electrical receptacles for use in combination therewith. Electronic circuitry systems, such as computers and other operating circuits, interface with the key-like devices through the receptacle. The keys contain a microelectronic circuit element, e.g., a microelectronic circuit chip or die, having an electrical lead or leads exposed along the length of the key for contacting electrical leads in the receptacle when the key is inserted therein and rotated to a "locked" position. The keys are particularly designed to interface with a processor and program memory system, that is, a computer.

Abstract: A multi-item data input apparatus for manual generation of data to designate selected ones of a plurality of items, the items being visibly displayed on a flat sheet, comprising a plate having apertures therein in positions corresponding to those of the items on the sheet, a transparent key mounted in each of the apertures and movable therein within a limited range, a contact spring actuatable by each key, and a matrix of conductor elements arranged in rows and columns in relation to the contact springs such that contact between two intersecting conductors is established by actuation of any of the keys, thereby generating data designating the item which is visible through that key.

Abstract: There is disclosed a conversion circuit arrangement for switching digital data signals between data terminals operating with different data transmission procedures. The circuit arrangement adapted for use with an electronic data switching system is composed of at least two interface circuits having input/output converting networks. External terminals of these interface circuits are connected to respective input/output means of the switching system for each type of data terminal. Internal input/output terminals of the interface circuits are connected to respective terminals of a storage unit. There is provided a control unit for controlling data transmission between the interface circuits and the storage unit and vice versa such that messages are buffered in the storage unit. The stored message is converted according to the data transmission procedure of the receiving data terminal.

Abstract: A portable two wire line test set having a self-contained source of electrical energy for powering a hybrid circuit and first and second amplifier means. The first amplifier receives and amplifies voice signals transmitted over the two wire line and the second amplifier amplifies and transmits voice signals over the two wire line. Transducer means are connected to both amplifiers to convert signals to audible sounds and vice versa. In an alternative embodiment a third tuned amplifier means is included for detecting and amplifying a signal in a predetermined frequency range so that the identity and condition of particular two wire lines may be determined.

Abstract: A line circuit includes a fixed resistance feed consisting of a pair of resistors connected in series with a d.c. power source and tip and ring leads of a communication line. A variable current feed includes a current sink and a current source also connected in series with the d.c. power source and the TIP and RING leads. Energizing current flow in the communication line results as the combination of currents passed by the two feeds. A control circuit determines the currents conducted by the current source and current sink and introduces variations in these currents in accordance with signals for transmission along the communication line. Differences between current flows in the variable current feed and current imbalance conditions on the communication line are accommodated by the fixed resistance feed which also determines the terminating impedance for the communication line.

Abstract: An optical encoder for providing an electrical signal having a frequency corresponding to the revolutions per minute of a motor shaft comprises a mounting member for securement to the motor, a shutter element for securement to the motor shaft and a top cover secured to the mounting member to sandwich the shutter therebetween. A photo cell is provided on the cover and a lamp housing providing a light source on the mounting member for shining light through the shutter to the photo cell. Rotation of the shutter then modulates the light beam to provide the desired signal. The lamp housing itself incorporates a built-in reflector with light bulb and is so designed as to be replaceable with respect to the mounting member so that heretofore provided lenses and the like are no longer necessary and the mounting arrangement is such that alignment accuracy with the photo cell is assured.