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

Function of the card:
SDTDL hs trigger

Saturated Drift Transistor Diode Logic (SDTDL) is a form of Diode-transistor logic using faster drift-field transistors.

Trigger is IBM's term for a flip flop or latch.

Part number: 372575

Customer Eng reference number: 734333

Used in: IBM 2821 Control Unit

Cap code: None (details)

References: IBM 2821 CCD, p87

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.