jmartin,

does this device contain any silicon at all ;-)

As far as I can remember it was released in the very early 80's

I guess it would be easier to put the SPO256A-AL2 to a museum and get a state of the art chip.

BTW.
The device is called:
Sierra Papa Oscar TWO FIVE SIX...
not
Sierra Papa ZERO TWO FIVE SIX...

SO you have probably been searching for the wrong thing.