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

Function of the card:
Alloy-Memory Thermal Switches

Listed in 1401 SMS card usage

Germanium alloy transistors were an early type of transistor, faster than the earlier grown-junction transistors.

Part number: 370425

PCB number: 484157

Used in: IBM 1401


IBM SMS card type AKB 370425 IBM SMS card type AKB 370425

References: 1_2 SMS Cards, p63
Coslet data
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.