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

Function of the card:
Alloy – Line Terminator, “N” Type

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

Part number: 371748

Used in: IBM 7090


DT: Driver. Terminator. A single-transistor class-A grounded-base amplifier used to terminate a transmission line.
IBM SMS card type RL 371748 IBM SMS card type RL 371748

Image courtesy of Computer History Museum

References: Drawing courtesy of Living Computers: Museum + Lab
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.