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

Function of the card:
Ctdl integrator u and t
Ctdl - integrator - u and - t
CTDL - Integrator _U and -T
CTDL-Integrator – U and – T

Listed in 1401 SMS card usage

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

Part number: 371996

Used in: IBM 1410, IBM 1414 I/O Synchronizer, IBM 1401

Cap code: XX (details)

IBM SMS card type NGXX 371996 IBM SMS card type NGXX 371996

Image courtesy of Randall Neff

References: 2_2 SMS Cards, p48
1410_SMS_VOL_2.pdf, p123
National Museum of Computing.
Coslet data
SMS Cap Code Templates & Index

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.