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

Part number: 370903

PCB number: 491123

IBM SMS card type AD 370903 IBM SMS card type AD 370903

Image courtesy of Henk Stegeman

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.