VPI II Overview - Alstom

Chassis Configurations3.3.1. CaseThe VPI II direct wired chassis can be constructed from two basic case configurations.One to four chassis can be used to complete a system. The chassis may be a mixtureof the two types. The two basic types are the split motherboard and the continuousmotherboard that busses the center connector (P2) of the printed circuit boardstogether. All chassis contain 21 printed circuit board slots.The split motherboard version of the chassis is configured to connect the P2 connectortraces from chassis slots one through five together and slots six through 21 together.Since the VPI II system uses the P2 connector as the I/O bus, this allows Vital and nonvitalI/O to be housed in the same chassis. For example, the first five chassis slots couldbe used to house non-vital I/O and the non-vital processor. Slots from 6 to 21 couldcontain Vital I/O along with the Vital I/O controller (I/O bus).NOTEOther system boards may also be required to configure a proper operatingsystem and several other arrangements could be possible.This chassis can also be supplied with an optional rear panel. This panel is used toprovide connection points for diagnostic equipment connections; chassis to chassisribbon cable connections and power supply connections.P2511G, Rev. Jan/06 3–6 ALSTOM Signaling Inc