Delta Products Z80 CPU Board
This board came out around 1978. It was the only Z80 board Delta made.

The board featured two serial ports (8251's) and a 24 bit parallel port (an 8255).  One M1 wait state could be added for slow memory. The board could be jumpered to run at 2 or 4 MHz.  There was room for an onboard EPROM which had to be a 2708 or 2716. It also had to reside at F800H for the onboard power on jump circuitry to work.

Other Delta Products S-100 Boards
Z80 CPU Board    FDC Board   64K Dynamic RAM Board