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

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

Part number: 371996

Field replacement part number: 371996

Customer Eng reference number: 729887

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

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

Image courtesy of Randall Neff

2_2 SMS Cards, p48.
1410_SMS_VOL_1.pdf/1410_SMS_VOL_2.pdf, p2123.
1414 SMS Cards, p75.
This page created by Ken Shirriff.

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.