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

Function of the card:
General Delay Circuit
General delay circuit

Listed in 1401 SMS card usage

Part number: 370703

Customer Eng reference number: 734348

PCB number: 484499

Used in: IBM 1401, IBM 2821 Control Unit

Symbol:DLY

DLY: Delay. Delays a pulse for a certain specified constant time.
IBM SMS card type AQQ 370703 IBM SMS card type AQQ 370703 IBM SMS card type AQQ 370703 IBM SMS card type AQQ 370703

Image courtesy of Henk Stegeman

References: Coslet data
IBM 2821 CCD, p21
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 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.