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

Function of the card:
Inverting power driver
SDTDL inverting power driver
Power inverter
Inverting Power 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: 370225

Customer Eng reference number: 729910

PCB number: 484041 , hole pattern: 491329

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


IP: Inverter, Power. Performs function of an inverter white also driving a line.
IBM SMS card type DFQ 370225 IBM SMS card type DFQ 370225 IBM SMS card type DFQ 370225 IBM SMS card type DFQ 370225

References: IBM 1311 ILD, p116
Coslet data
1410_SMS_VOL_1.pdf, p42
2_2 SMS Cards, p78
IBM 1443 ALD, p92
IBM 2821 CCD, p43
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.