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

Function of the card:
SDTDL 3 way n and log blk w/o lds

Exists in SLT version.

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

Part number: 372588

SLT modules: 2399110, 361431

Customer Eng reference number: 734402

Used in: IBM 2821 Control Unit

IBM SMS card type ZGK 372588 IBM SMS card type ZGK 372588 IBM SMS card type ZGK 372588 IBM SMS card type ZGK 372588

Image courtesy of Henk Stegeman

References: IBM 2821 CCD, p114
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 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.