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

Function of the card:
Ctrl-emitter followers, low current
CTRL-Emitter Followers,Low Current [Photo Diode Sensor-DE]

Quad Emitter Follower (Photodiode Amplifier)

Complemented Transistor Resistor Logic (CTRL) is IBM's term for a form of resistor-transistor logic.

Part number: 2115030

Used in: IBM 1620


AM: Amplifier. Provides increased strength to a detected signal or pulse.
IBM SMS card type CBW 2115030 IBM SMS card type CBW 2115030


A O1
B I1
C O2
D I2
E O4
F O3
G I4
H I3
L +12V
M -12V
Q +12V
References: IBM 1620 Instructional System Diagrams, p488
Coslet data

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.