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

Function of the card:
Alloy-relay driver
Allow-Relay Driver
Relay Driver
Alloy-Relay 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: 371078

Used in: IBM 1401, IBM 1410, 7030, IBM 1414 I/O Synchronizer, 7040

Symbol:RD

IBM SMS card type QD 371078 IBM SMS card type QD 371078 IBM SMS card type QD 371078 IBM SMS card type QD 371078 IBM SMS card type QD 371078 IBM SMS card type QD 371078

Image courtesy of Randall Neff

References: 1410_SMS_VOL_2.pdf, p64
Coslet data
National Museum of Computing.
2_2 SMS Cards, pp55,56,57
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.