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

Function of the card:
SDTDL - Address Register
Address resister
SDTDL address register

Saturated Drift Transistor Diode Logic (SDTDL) is a form of Diode-transistor logic using faster drift-field transistors.

Part number: 372221

Customer Eng reference number: 734393

Used in: IBM 1443 Printer, IBM 2821 Control Unit

IBM SMS card type YKS 372221 IBM SMS card type YKS 372221

References: IBM 1443 ALD, p119
IBM 2821 CCD, p95
National Museum of Computing.
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.