Replicating IBM SLT/MST card interconnect

Tom Stepleton stepleton at
Thu Jul 29 07:21:27 CDT 2021

Hi cctalk,

I'm looking to replicate the 24-contact connector system that IBM used on
SLT and MST cards for many years. Has anyone done this before?

The best photos of this connector that I can find online are on this page:
I haven't searched Bitsavers documentation extensively for IBM
specifications, but I've seen some details around page 54 of this document:,SLD,ASLT,MST_TO_Oct71.pdf

I'm interested in reproducing both polarities of this connector: plug and
socket. Also, even though the most familiar use of this connector is for
board-to-board interconnect, I'm most interested in wire-to-board
interconnect. IBM used this method for DC power connectors in its  5100,
5110, and 5120 computers. Here are images of this specific connector:
taken as still images from a YouTube video on the IBM 5120 by Jerry Walker (

I've designed and built a device that monitors DC power supply voltages for
overvoltage and undervoltage excursions and cuts off all power rails if any
voltage goes out of spec. I hope to use it to protect my own IBM 5100 from
major power supply faults like the one CuriousMarc encountered with his

In order to put my device between my 5100's power supply and the logic card
backplane, I need to recreate a plug and a socket so that I can fashion a
cable that goes out to my device. If anyone has created dependable modern
versions of these connectors, would you mind sharing any pointers?

Thanks for any help,

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