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

Function of the card:
SDTDL 10 way log blk low sp w load
10 Way Logic Block Low Speed with Loads
10 way logic block low speed with load
SDTDL 10-way logic block low speed with load

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: 370373

Customer Eng reference number: 729919

PCB number: 484077

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

IBM SMS card type DGZ 370373

References: 1410_SMS_VOL_1.pdf, p97
Coslet data
2_2 SMS Cards, p92
IBM 1311 ILD, p124
IBM 2821 CCD, p56
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.