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

Function of the card:
Ctdl logic inverter pnp all loads
Ctdl logic inverter pnp no loads
CTDL-Logic Inverter PNP All Loads
CTDL Logic Inverter (PNP)
CTDL Logic Inverter PNP All Loads

Listed in 1401 SMS card usage

Complemented Transistor Diode Logic (CTDL) is IBM's term for a form of diode-transistor logic.

Part number: 371077

Used in: IBM 1410, IBM 1401, IBM 7070, IBM 1414 I/O Synchronizer, 7030

Cap code: VB (details, details)

Symbol: I

I: Inverter. Changes a positive input to a negative output, or vice versa.
IBM SMS card type JLVB 371077 IBM SMS card type JLVB 371077 IBM SMS card type JLVB 371077 IBM SMS card type JLVB 371077 IBM SMS card type JLVB 371077

Image courtesy of Randall Neff
Image courtesy of Henk Stegeman

References: 2_2 SMS Cards, p35
National Museum of Computing.
IBM Standard Modular System, Component Circuits, p161
1410_SMS_VOL_2.pdf, p63
Coslet data
SMS Cap Code Templates & Index
1401 Pocket Reference Manual

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.