Abstract: Method and apparatus for storing and retrieving routing information in a node of a network, such as an ATM network, are disclosed. A routing table in each node of the network stores the routing information for each active call connection through the node, for example, identified by a virtual path identifier (VPI) and a virtual channel identifier (VCI). The routing table is indexed by a modified header error control (HEC) value, which may be the actual HEC value associated with a given cell, or a value calculated therefrom. Upon receipt of an incoming cell at a network node, the modified HEC value is calculated, to access the appropriate entry of the routing table. The routing table preferably stores a pointer to a memory location, such as a linked list of data structures, storing the actual routing information for each connection.

Abstract: A multi-chip module is composed of two or more integrated-circuit chips located on a substrate such as a dielectrically coated silicon substrate. The chips are interconnected by means of transmission wiring lines. At least some of the chips contain one or more input buffer circuits, each composed of two branches ("legs"). Each such branch contains, in one embodiment, an n-channel MOS transistor connected in series with a pair of series-connected p-channel MOS transistors--whereby, in each such branch, one of the p-channel MOS transistors is located between (intermediate) the other of the p-channel MOS transistors and the n-channel MOS transistor of that same branch. On the other hand, in each buffer circuit, the intermediate p-channel MOS transistors of both branches are cross-coupled.

Abstract: A battery feed circuit for supplying DC power to a telephone loop and for coupling signals to and from said loop is disclosed. A differential amplifier having its inputs connected by way of a twisted resistive bridge to the telephone loop provides a voltage at its output which includes the signal from said telephone loop and has a DC component which is proportional to the DC current flowing in the loop. Signals are coupled to the telephone loop by a low-inductance three-winding transformer which has two of its windings connected in series with an external power supply and the twisted bridge in order to supply current to the telephone loop. A second differential amplifier is connected in different ways in several embodiments between the output of the first differential amplifier and the third winding of the transformer to provide an automatic flux-cancelling action in order to avoid saturation of the transformer core.

Abstract: A line current measuring arrangement employs two matched toroidal cores with line windings, control windings, sense windings, and feedback windings. The line windings cause equal amounts of the same polarity of magnetizing intensity H in the two cores when a line current flows. The control windings are pulsed by control current pulses to cause equal changes of opposite polarity of control H in the two cores to drive the two cores to saturation of magnetic induction B. The sense windings are serially opposed so that the changes of B in the two cores cause sense voltages in polarity opposition. Any difference in the sense voltages, due to the presence of line current H, is cumulatively and algebraically integrated to provide a changing output voltage which is a measure of the cumulative integration. The output voltage causes feedback H in both cores in opposition to any line H.