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

Function of the card:
CTRL Light Driver N Type
Ctrl light driver n type

Hex Lamp Driver 15mA

Complemented Transistor Resistor Logic (CTRL) is IBM's term for a form of resistor-transistor logic.

Part number: 371943

PCB number: 493239

Used in: IBM 1620, 7030, IBM 1311 Disk, 1622, 1626

Symbol:LD, DI

IBM SMS card type AFR 371943 IBM SMS card type AFR 371943


A I1
B O1
C I5
E I2
F O2
G I6
H O6
K O4
L O5
N +12VM
P I3
Q O3
R I4
References: IBM 1620 Instructional System Diagrams, p471
Coslet data
1626 Plotter Parts
IBM 1311 ILD, p92
National Museum of Computing.
IBM 1620 FE Catalog

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, 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.