The pulse processors in question (Kevex 4460/4461 and 4405) are NimBin style (KimBin) components. The pulse processor connection to both the pre-amp and the existing Kevex computer system is made through a card-edge connector to the crate backplane and cannot be easily tapped. The only way to connect a 3rd party system to these pulse processors is to implement a "bridge," a small in-line interface card designed to tap/inject the appropriate signals.

4pi designed and sold a bridge to facilitate the connection of our system to the 44xx series of pulse processors; the remaining description is a summary of the device; however, 4pi no longer manufactures the bridge and to our knowledge there is no other way to connect a 3rd party system to these pulse processors.

The bridge itself is a slim card which fits between the pulse processor card-edge connector and the backplane. When installed, the pulse processor cannot be pushed all the way back into its slot. A cable is hardwired to the bridge (cannot be removed) to make the connection between the pulse processor and the 4pi Scanning Interface Unit.

The bridge intercepts the signals from the pulse processor to the backplane. The bridge circuitry consists of a Programmable Array Logic (PAL) chip and an analog buffer for the PHA pulse. The pulse processor gets its power from the backplane and the Kevex controller (typically a Kevex Delta or 8000 system) is hardwired to it through the KimBin crate. Therefore, the Kevex control system must be present and powered up for the bridge and pulse processor to work.

In addition, the Kevex start-of-conversion circuitry passes through the backplane, and that signal must be present for the pulse processor to work. Either the Kevex Delta/8000 system must supply this signal, or 4pi must. If the Kevex system is to supply this signal, then not only must it be powered on, but it must also be running its EDS spectrum acquisition software simultaneously. If the 4pi system is to supply this signal, then the Kevex system has to powered up, but does not have to be running its EDS software. 4pi must know in advance which of these setups will be used, because the PAL is programmed accordingly.