The idea is impressive, but that PCB is huge. Any chance the design could be made smaller? Jim Hi Jim I was thinking more about your question. The system in the photos is using a standard PropIO board with a *prototype* CPU adapter "shim socket" which would *not* be part of the final design. If the tests prove out then the perfboard and ribbon cable would be replaced with a 2"x1.5" shim socket PCB that would plug in under the host Z80 CPU. It would export the Z80 pins out to 40 pin dual row header. The PropIO would connect to the shim socket PCB via a 40 conductor ribbon cable. So yes, in that sense the system would be smaller than what is pictured in the N8VEM post. It would be functionally identical. I hope that clarifies things. Thanks and have a nice day! Andrew Lynch