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

Function of the card:
10-Way Logic Block Low Speed without Loads
10-way logic block low speed without loads
SDTDL 10-way logic block low speed without 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: 370374

PCB number: 484077

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

IBM SMS card type DHA 370374 IBM SMS card type DHA 370374

References: 2_2 SMS Cards, pp93,94
Coslet data
1410_SMS_VOL_1.pdf, p98
IBM 1311 ILD, p125
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 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.