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

Function of the card:
Ctrl - inverter "n" 2 way extender
CTRL-Inverter "N" 2 Way Extender
Ctrl- inverter n 2 way extender

Quad 2 Input Open Collector NAND

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

Part number: 370322

PCB number: 492867

Used in: IBM 1620, IBM 1311 Disk

Symbol:I, A, O


A I2
B I1
C O3
D I1
E I3
F I3
G O1
H I2
K O4
M -12V
N +12VM
P O2
Q I4
R I4
References: Coslet data
IBM 1620 Instructional System Diagrams, p472
IBM 1311 ILD, p92

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.