Function of the card:
SDTDL low speed trigger
Trigger ls
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: 372239
Customer Eng reference number: 734347
PCB number: 484991 , hole pattern: 493457
Used in: IBM 1443 Printer, IBM 2821 Control Unit
Cap code: None (details)
Symbol: E, T
E: Extender. Provides additional inputs to logical blocks and triggers. Adds to drivers the ability to drive more loads.
T: Trigger. A conditioned bi-stable device whose steady-state outputs change from one stable state to the other with two separate triggering levels, pulses, or voltage changes. The set input turns the trigger on if the reset input Is not on, and vice versa.
IBM 2821 CCD, p35
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.