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

Function of the card:
Ctdl - emitter follower pnp
CTDL-Emitter Follower PNP
Emitter Follower PNP

Listed in 1401 SMS card usage

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

Part number: 371259

PCB number: 491005

Used in: IBM 1401, IBM 1410, 7030, IBM 7070

Symbol:DE

DE: Driver Emitter Follower. A driver, operating on the emitter follower principle, used for power amplification, impedance matching, and isolation without inversion. Often used as a logical element.
IBM SMS card type CPWT 371259 IBM SMS card type CPWT 371259 IBM SMS card type CPWT 371259 IBM SMS card type CPWT 371259 IBM SMS card type CPWT 371259 IBM SMS card type CPWT 371259

Image courtesy of Randall Neff
Image courtesy of Henk Stegeman

References: IBM Standard Modular System, Component Circuits, p52
Coslet data
1410_SMS_VOL_2.pdf, p71
1_2 SMS Cards, p105
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 bitsavers.org, 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.