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

Function of the card:
Ctrl-inverter "n" 2 way
CTRL Inverter "N" 2 Way
Crtl - inverter "n" 2 way
Ctrl - inverter n 2 way
CTRL-Inverter "N" 2 Way Extender
Ctrl-inverter 4 2 way

Listed in 1401 SMS card usage
Quad 2 Input Open Collector NAND

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

Part number: 371661

PCB number: 492867

Used in: IBM 1410, IBM 729V, 7040, IBM 1311 Disk, IBM 1414 I/O Synchronizer, 1622, IBM 1620, 1626

Cap code: None (details)

Symbol: O, E, A, O

IBM SMS card type MX 371661 IBM SMS card type MX 371661 IBM SMS card type MX 371661 IBM SMS card type MX 371661

Image courtesy of Roberto Gonzalez Rocha
Image courtesy of Henk Stegeman

Pinout:

A I2
B I1
C O3
D I1
E I3
F I3
G O1
H I2
J GND
K O4
L O2R
M -12V
N +12VM
P O2C
Q I4
R I4
References: IBM 1620 FE Catalog
IBM 1620 Instructional System Diagrams, p485
Coslet data
IBM 1311 ILD, p134
1410_SMS_VOL_2.pdf, p104
National Museum of Computing.
1626 Plotter Parts

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.