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

Function of the card:
Overvoltage Protection 30 Volt

IBM SMS card type YGD IBM SMS card type YGD

References: Coslet data
1_2 SMS Cards, p12
This page created by Ken Shirriff on Wed Sep 15 18:15:11 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.