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

Function of the card:
P to N Buffer Converter (both loads)

Part number: 371345

Used in: IBM 7090


CB: Converter Buffer. A converter block that uses the current mode transmission line driver signal sent from a transmitting frame to generate voltage swings referenced to voltage planes of other frames.
IBM SMS card type DFYU 371345 IBM SMS card type DFYU 371345

Image courtesy of Computer History Museum

References: IBM Standard Modular System, Component Circuits, p83
This page created by Ken Shirriff on Wed Sep 15 18:15:10 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.