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

Function of the card:
Current Mode, Minus N Line Indicator

Part number: 371049

Used in: 7030, IBM 7090

Symbol:DI

DI: Driver, Indicator. Driver operating into an indicating device.
IBM SMS card type HX 371049 IBM SMS card type HX 371049

Image courtesy of Computer History Museum

References: IBM Standard Modular System, Component Circuits, p155
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 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.