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

Function of the card:
SDTDL inverter low speed w/o load
SDTDL inverter low speed w/0 load
Inverter-no load
SDTDL-Inverter Low Speed w/o 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: 370372

Customer Eng reference number: 729922

PCB number: 484123

Used in: IBM 1410, IBM 1311 Disk, IBM 1401, IBM 1443 Printer, IBM 2821 Control Unit

Cap code: None (details)

IBM SMS card type DHC 370372 IBM SMS card type DHC 370372 IBM SMS card type DHC 370372

References: IBM 1311 ILD, p126
1410_SMS_VOL_1.pdf, p96
2_2 SMS Cards, p97
IBM 1443 ALD, p101
IBM 2821 CCD, p58
Coslet data

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.