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

Function of the card:
Core matrix card

Part number: 373432

Customer Eng reference number: 822938

PCB number: 490322 , hole pattern: 748515

Used in: IBM 2821 Control Unit

Cap code: None (details)

References: IBM 2821 CCD, pp107,108,109

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.