Abstract: A method and apparatus for hot-plugging circuit boards having lower voltage logic devices into a higher voltage backplane in a manner that minimizes overvoltage stress during system power-up, or during a lower voltage power failure. The method and apparatus ensures that the lower voltage device(s') power input reaches at least a nominal input level before any other inputs of the device are driven to a level greater than or equal to an expected input level. Dedicated output pins on lower voltage logic device(s) are configured to issue a control output signal for enabling higher voltage devices. Output enable terminals for the higher voltage parts, which are connected to respective control outputs from a lower voltage device, are normally in a disabled state as a function of pull-up or pull-down circuitry.

Abstract: A modular memory array configuration uses a combinatorial decoding device (decoder), instead of straight buffering, to effect optimal delivery of control and address signals. Each port accessing memory on the array drives a single copy of address and control signals, plus bank select signals, over a shared interface to the decoder. Bank select controls the decoder which drives the address and control to only the accessed bank. Address and control signals to all banks but the accessed bank, are pulled up (inactive) with resistors on the memory array. For N banks, log2 N bank select bits are needed. The decoder device does not need to be clocked and therefore avoids problems associated with selecting between and providing asynchronous or redundant clocks for a multi-ported shared memory with ports independent of and asynchronous to one another.

Abstract: A roll stand for holding rolls of material such as paper rolls which allows the rolls to be mounted and material fed out. The roll stand includes a roll supporting bar which is raised and lowered by a mechanical system such as an air piston. The roll supporting bar is lowered to allow a roll of material to be mounted, and then raised to allow the roll to turn freely. The roll stand includes a roll retainer, including a bar which swings down against the end of the roll, to keep the roll properly positioned on the roll supporting bar. The roll retainer swings up out of the way while a roll of material is mounted or removed. A rotating mechanism maintains the roll retainer in whatever position it is moved to. The roll stand may also be configured to support a plurality of rolls, each roll lifted into place on its own roll supporting bar. The roll supporting bars are positioned to hold all the rolls with a minimum of floor space.