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

Function of the card:
Alloy-Indicators, Lamp, VM
Voltage Mode 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: 371048

Used in: IBM 729V, IBM 1410, 7030


DI: Driver, Indicator. Driver operating into an indicating device.
IBM SMS card type HW 371048 IBM SMS card type HW 371048

References: IBM Standard Modular System, Component Circuits, p219
1410_SMS_VOL_2.pdf, p61
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.