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

Function of the card:
SDTRL-alloy switch
SDTRL-Alloy Switch

Dual ?

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

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

Part number: 370171

Used in: 7030, 1622, IBM 1620

Cap code: None (details)

Symbol: SW

Pinout:

A I1
B O2A
C O2B
D OCB
E I2
F O1A
G OCA
H O1B
J GND
K IE
L +12V
M -12V
N
P
Q +12V
R
References: IBM 1620 FE Catalog
IBM 1620 Instructional System Diagrams, p493
Coslet data

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.