This is really where I started in the electronics industry back in
1980. I started work for a company called ASD Engineering
who were designing Z80 based eurocard systems, and custom
electronic products. I still have a few of the old cards here.
This one is a PEZ8040 single board computer.
Based on a 4MHz Z80 processor it has serial , parallel and clock lines brought out to the I/O connector and can be interconnected with other PEZ series cards through the system connector (in a backplane)
The system bus/backplane is based on the Z80 bus used in the Mostek AID80F development system. ASD had a couple of these running FLP80DOS but after a while they were also running CP/M 2.2