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

Function of the card:
1-2 Way, 1-3 Way 2/Card (-A -O)
SDTDL 1-3, 1-2 way -a-o 2/card load
1-3 way 1-2 way-load

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

Part number: 372202

Customer Eng reference number: 734309

PCB number: 493457

Used in: IBM 1443 Printer, IBM 2821 Control Unit

IBM SMS card type AXC 372202 IBM SMS card type AXC 372202 IBM SMS card type AXC 372202

Image courtesy of Roberto Gonzalez Rocha

References: IBM 1443 ALD, p81
National Museum of Computing.
IBM 2821 CCD, p24
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.