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

Function of the card:
Dj diode clamp

Part number: 370690

Customer Eng reference number: 734325

PCB number: 492345

Used in: IBM 2821 Control Unit


D: Driver. Isolates a signal from its generating source and uses it to drive one or more other circuits without affecting or overloading the generating circuits. Can be used to supply the required power directly or only to activate the circuit through which power is actually supplied.

References: IBM 2821 CCD, p20
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.