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

Function of the card:
N Type Line Terminator
Ctdl - pnp line terminator

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

Part number: 371518

PCB number: 493191

Used in: IBM 1410, 7030, IBM 7070


DT: Driver. Terminator. A single-transistor class-A grounded-base amplifier used to terminate a transmission line.

References: IBM Standard Modular System, Component Circuits, p58
1410_SMS_VOL_2.pdf, p85
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.