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

Function of the card:
SDTRL Standard Cable Terminator Gated
Simplex Interface Terminator Gated
SDTRL standard cable terminator gated

Quad NAND Line Receiver

Saturated Drift Transistor Resistor Logic (SDTRL) is a form of resistor-transistor logic using faster drift-field transistors.

Part number: 371988

PCB number: 493261

Used in: IBM 1620, 1622


DT: Driver. Terminator. A single-transistor class-A grounded-base amplifier used to terminate a transmission line.
IBM SMS card type DEE 371988 IBM SMS card type DEE 371988


A O2
B O1
C O3
D I2
E I3
F C3
H I4
K C2
M -12V
N +12VM
P C1
Q I1
R C4
References: IBM 1620 Instructional System Diagrams, p481
Coslet data
National Museum of Computing.
IBM 1620 FE Catalog

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, 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.