Mostly 68. There is centronics 50 pin, HD 50 pin or HD 68 pin. Also some micro D-type connectors, and cheap-junk SCSI uses 25 pin but don't buy it. Also, SATA and various other modern interfaces are basically SCSI logical protocol over a serial layer 0.
50 pins.
50 pins.
The beauty of SCSI is that supports many physical interfaces. Fibre channel SCSI uses 4 "pins" which can be copper, or fibre optic cabling. Parallel scsi which you are probably asking about can use 25, 50 or 68 pins. So you should rephrase your question to specify the interface you are asking about ... but I guess that would liook kinda dumb, ... "How many pins does a 50-pin SCSI interface have" :)
68 pins.
68
Typically the narrow scan cable has 50 pins.
SCSI interface would be what you're looking for.
Why is there confusion between EIDE and SCSI drive interface standards
I am assuming you mean what is SCSI used for? In this case, SCSI does NOT mean "small computer serial interface," instead, it means "Small Computer SYSTEM Interface." SCSI is used as a fast interface between a host adapter and the CPU that can daisy chain as many as 7 or 15 devices on a single bus.
SCSI is an acronym for Small Computer Systems Interface.
A CD drive can interface with a mother board using an EIDE, SATA or SCSI interface.
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