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

Function of the card:
CTDL Single Shot "U" Input
Ctdl single shot u input
Ctdl single shot "u" input
CTDL-Single Shot ā€œUā€ Input
CTDL Single Shot Trigger (U 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: 371592

Used in: IBM 1401, IBM 1410, 7030, IBM 1414 I/O Synchronizer, 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 NC 371592 IBM SMS card type NC 371592 IBM SMS card type NC 371592 IBM SMS card type NC 371592

Image courtesy of Henk Stegeman

References: Coslet data
IBM Standard Modular System, Component Circuits, p178
2_2 SMS Cards, pp44,45,46
1410_SMS_VOL_2.pdf, p93
National Museum of Computing.
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.