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

Function of the card:
Alloy-Indicator Driver 40 mA
Alloy - indicator driver 40 ma
High Current Indicator Driver

Listed in 1401 SMS card usage

Germanium alloy transistors were an early type of transistor, faster than the earlier grown-junction transistors.

Part number: 371546

Used in: IBM 1401, IBM 1410, IBM 7070


DI: Driver, Indicator. Driver operating into an indicating device.
IBM SMS card type KA 371546 IBM SMS card type KA 371546 IBM SMS card type KA 371546 IBM SMS card type KA 371546

Image courtesy of Randall Neff
Image courtesy of Henk Stegeman

References: 1410_SMS_VOL_2.pdf, p91
IBM Standard Modular System, Component Circuits, p166
Coslet data
2_2 SMS Cards, p41
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.