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

Function of the card:
Ctdl pnp - inverter latch
Ctdl pnp inverter latch
CTDL PNP-Inverter Latch

Listed in 1401 SMS card usage

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

Part number: 370143

Field replacement part number: 370143

Customer Eng reference number: 729818

PCB number: 493337

Used in: IBM 1401, IBM 1410

References: 1_2 SMS Cards, p80
Coslet data
1410_SMS_VOL_1.pdf, p15
This page created by Ken Shirriff on Wed Sep 15 18:15:11 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.