Вот немного информации

Mitsubishi MF504C-310MP 5.25" DD/HD
PC-AT/386 link settings; names are conjecture

IP no pins
SG
SB closed 300/360 rpm
SS 300 rpm only
NO


DS0
DS1 closed
DS2
MX
DS3


DD
HR
IL
IS
MM closed motor start with MotorOn
MS motor start with Select
IR internal Ready?
IU In Use?
RI closed
RD closed Ready?
DC closed Disk Changed? then why RD and DC both made?
SR Speed Ready?