Having read the specs several times on the SII chip for the KA640 I can 
assure you that no, it cannot be used in "SCSI" mode. Two problems at least 
are that the 50 pin connector is wired up incorrectly and the termination 
is different.

That being said, the KN20 (the DECServer 5500) CPU, uses the SII chip in 
SCSI mode by making basically those changes as far as I can tell.

As for my efforts toward a working SII driver, they have been stalled by 
lack of time, the fact that I changed jobs and in the process had to move 
my entire VAX collection into storage. If I can get a 5KW PV system 
installed this summer then that will alleviate the power issues in Sunny 
California.

--Chuck