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

Function of the card:
SDTDL-four 2 way n and logic blocks with loads
2 way -a hs
SDTDL - four 2 way n and logic blocks with loads
SDTDL-Four 2 Way N And Logic Blocks with Loads

Listed in 1401 SMS card usage

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

Part number: 370216

Customer Eng reference number: 729906

PCB number: 399585

Used in: IBM 1443 Printer, IBM 1401, IBM 1311 Disk, IBM 1410

IBM SMS card type DEF 370216 IBM SMS card type DEF 370216

References: 1410_SMS_VOL_1.pdf, p33
Coslet data
IBM 1443 ALD, p89
2_2 SMS Cards, p72
IBM 1311 ILD, p112
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.