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

Function of the card:
Three-Way OR, Type B (in-phase load)

Part number: 371341

Used in: IBM 7090


+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 DFYZ 371341 IBM SMS card type DFYZ 371341

Image courtesy of Computer History Museum

References: IBM Standard Modular System, Component Circuits, p85
This page created by Ken Shirriff on Wed Sep 15 18:15:09 2021.

The information on these pages comes from a variety of sources, especially old IBM documents on, 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.