I suspect this is quite on topic. I have acquired a 5 1/4" magneto optical disk drive that is equivalent to a Sony SMO S501. The label says it was put together by DYNATEK Automation Systems. I suspect that the two internals are a C501/D501 from Sony in any case with just the external box and power supply being from Dynatek. SW1 is an unusual rotary switch which is used to select the SCSI ID - I have tested that and confirmed that it works. The drive works quite well as the last drive in the daisy chain, so I presume that a terminator and terminator power are part of the selectable equipment. Of course, the drive works very well as the only drive on the host adapter. My question concerns SW2 which is an 8 position dip switch. On the Sony drive, there is ONLY an 8 position dip switch with 3 positions being used for SCSI ID. Might anyone have some documentation on which parts of the dip switch on the Dynatek drive are used and for what?