This can program the 27xxx series
from 2732 to 27513 EPROMs as well
as some NVRAM devices. Devices
larger in size than 32k x 8 use
the floppy disk as a 'memory swap'
data buffer.
The card's length is extended so
that the EPROM socket isn't
covered by the card plugged-in
in front of it.

The trimpots calibrate the socket
Vcc and Vpp voltages:
5v, 6v, 12.5v, 21v, 25v
The voltages are selected and the
socket is configured via a PIA:
(Hitachi HD468B21P) "6821" or "6520"
The socket address and data busses
are accessed via a PPI:
(NEC D71055C) "8255"