Abstract: In a "Futurebus+" backplane, at each end of the backplane the signal lines are each electrically connected to a power bus on a face of the board or to a power plane encapsulated in the board via a discrete resistor mounted on the face of the board and separately formed with respect to the other resistors and the ground lines are each electrically connected to the power bus or power plane via a discrete capacitor mounted on the face of the board and separately formed with respect to the other capacitors. Preferably, at each end of the backplane the discrete resistors and capacitors are mounted on both faces of the board, the number on one face being approximately the same as the number on the other face. In the event that a resistor or capacitor should be faulty, only the signal or ground line to which the faulty resistor or capacitor is connected will be out of service until the faulty resistor or capacitor is replaced.

Abstract: In a "Futurebus+" backplane, at each end of the backplane the signal lines are each electrically connected to a power bus spaced from the rear face of the backplane via a discrete resistor which is housed in a throughbore in a body of electrically insulating material detachably secured to the rear face of the bakplane and which is electrically connected between the power bus and a pin soldered in a plated through hole and interconnected in the signal line. The ground lines are each connected to the power bus via a discrete capacitor which is housed in a throughbore in the body and which is electrically connected between the power bus and a pin soldered in a plated through hole and interconnected in the ground line. In the event that a resistor or capacitor should be faulty, only the signal or ground line to which the faulty resistor or capacitor is connected will be out of service until the faulty resistor or capacitor is replaced.

Abstract: A kit of parts for assembling an adaptor for electrically connecting a surface mounted component to a perforated circuit board comprises a multiplicity of wire wrap contact pins each having, integral with the trailing end of the pin and extending laterally with respect to its axis, an arm which, when the pin is engaged in a hole in a circuit board, bears against a major surface of the board and constitutes a footprint of the adaptor. The multiplicity of wire wrap pins comprise at least two groups of wire wrap pins, the lateral arms of the pins of each group being identical to one another and the lateral arms of the pins of one group differing from the lateral arms of the pins of each other group.

Abstract: A hand-held shot tube detonator including a primer and shot tube holder removably mounted on a firing pin body having a flash guard movable between extended and retracted positions. The flash guard is retracted to permit mounting of the holder on the body and is then extended to surround the holder to channel the flash and explosive gases away from the operator when the detonator is fired.