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

Function of the card:
Spd-current drive

Part number: 374907

Customer Eng reference number: 837973

Used in: IBM 2821 Control Unit

IBM SMS card type ESG 374907 IBM SMS card type ESG 374907

References: IBM 2821 CCD, p82
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, 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.