This page describes the IBM SMS card "DFZA", and is part of the SMS card database.

Function of the card:
Three-Way OR, Type B (both loads)

Part number: 371340

Used in: IBM 7090

Cap code: ZA (details)

Symbol: +O

+O: Positive OR. In-phase output is positive if one or more input signals are positive. Out-of phase output is negative for the above condition.
IBM SMS card type DFZA 371340 IBM SMS card type DFZA 371340

Image courtesy of Computer History Museum

References: IBM Standard Modular System, Component Circuits, p85
SMS Cap Code Templates & Index

The information on these pages comes from a variety of sources, especially old IBM documents on bitsavers.org, as well as information from the IBM 1401 restoration team, especially Tim Coslet's SMS data and Jim Hunt's data. Much of this information was obtained through OCR, so don't expect complete accuracy. These pages are not associated with IBM in any way.