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

Function of the card:
Indicator Driver
Sdttl indicator driver
SDTDL indicator driver

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: 370347

Field replacement part number: 370347

Customer Eng reference number: 729912

PCB number: 484121

Used in: IBM 1401, IBM 1311 Disk, IBM 1410, IBM 2821 Control Unit

IBM SMS card type DGS 370347 IBM SMS card type DGS 370347 IBM SMS card type DGS 370347 IBM SMS card type DGS 370347

References: IBM 2821 CCD, p49
1410_SMS_VOL_1.pdf, p86
Coslet data
2_2 SMS Cards, pp81,82
IBM 1311 ILD, p121
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.