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

Function of the card:
CTDL Single Shot Trigger (T Input)
CTDL-Single Shot “T” Input
Ctdl single shot "t" input

Listed in 1401 SMS card usage

Complemented Transistor Diode Logic (CTDL) is IBM's term for a form of diode-transistor logic.

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

Part number: 371591

Used in: IBM 1401, IBM 1410, IBM 7070


SS: Single Shot. Provides a monostable output which can be pulsed into its quasi-stable state for a predetermined duration. with each input triggering pulse or triggering voltage change. Once triggered, the output pulse duration becomes independent of input time duration or amplitude.
IBM SMS card type NB 371591 IBM SMS card type NB 371591 IBM SMS card type NB 371591 IBM SMS card type NB 371591

Image courtesy of Henk Stegeman

References: 2_2 SMS Cards, pp42,43
1410_SMS_VOL_2.pdf, p92
Coslet data
IBM Standard Modular System, Component Circuits, p177
This page created by Ken Shirriff on Wed Sep 15 18:15:10 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.