The Intel 8044 (also known as the RUPI-44) is an 8-bit microcontroller from the 1980s.
It has the 8051 core, combined with a built-in SDLC/HDLC serial communication coprocessor.
The Intel real-time operating system RMX51 is embedded in the ROM code.
It supports hardware SDLC and HDLC protocols for fast data transmission up to 2.4 Mbps.
It was widely used in industrial networks like BITBUS.
To experiment with it, I have the following:
Two standalone communication boards
Two ISPC development boards
A PC card for one of these development boards
The full documentation
So a total of 4 8044 microcontrollers on an IC socket