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

Function of the card:
Ctdl hi speed 2 way and pnp fld rep
CTDL-High Speed - Two Way “And” PNP No Loads
Two-Way -AND (no 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: 371583

Field replacement part number: 370983

Used in: IBM 1401, IBM 7070


-A: Negative AND. In-phase output is negative only when all inputs are negative. Out-of-phase output is positive for the above condition.
IBM SMS card type JG 371583 IBM SMS card type JG 371583 IBM SMS card type JG 371583 IBM SMS card type JG 371583

Image courtesy of Henk Stegeman

References: 1_2 SMS Cards, p38
Coslet data
2_2 SMS Cards, p24
IBM Standard Modular System, Component Circuits, p158
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.