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

Function of the card:
Alloy-Universal Delay Circuit

Listed in 1401 SMS card usage
One Shot, programmable & adjustable (basic 7-36uS)

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

Part number: 371884

PCB number: 492741

Used in: IBM 1401


DLY: Delay. Delays a pulse for a certain specified constant time.
IBM SMS card type AAF 371884 IBM SMS card type AAF 371884


A CAP (6mS-30mS)
B I1
C CAP (60uS-340uS)
F CAP (300uS-1.7mS)
K -6V
L +6V
M -12V
N O1
P I1
Q +6VM
R -12VM
References: 1_2 SMS Cards, p48
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.