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

Function of the card:
CTDL- 3-Way “And” NPN
Three-Way +AND (2 loads)

Listed in 1401 SMS card usage

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

Part number: 371254

Used in: IBM 1401, IBM 7070

Cap code: WV (details)


+A: Positive AND. in-phase output is positive only when all inputs are positive. Out-of-phase output is negative for the above condition.
IBM SMS card type CKWV 371254 IBM SMS card type CKWV 371254

Image courtesy of Henk Stegeman

References: IBM Standard Modular System, Component Circuits, p46
Coslet data
1_2 SMS Cards, pp34,96
1401 Pocket Reference Manual
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.