DEC equipment had something similar. A 6 pin "MMJ" connector. It almost looks like RJ45 except the clip was off center.

I also remember some 90's terminal servers that had enormous "octopus" cables. There was a single connector on the box that broke out to 8 to 16-ish DB25 serial ports.

Some DEC equipment in the QBUS era also used DE9 serial ports, with a different pinout than IBM's.