Parallel communication modern computers. Before the development of high-speed serial technologies, the choice of parallel links over serial links was driven by these factors: The decreasing cost and better performance of integrated circuits has led to serial links being used in favor of parallel links; for example, IEEE 1284 printer ports vs. USB, Parallel ATA vs. Serial ATA, and FireWire or Thunderbolt are now the most common connectors for transferring data from AV(audiovisual) devices such as digital cameras or professional-grade scanners that used to require purchasing a SCSI HBA years ago. One huge advantage of having fewer wires/pins in a serial cable
Parallel SCSI of the standard has ever specified what kind of connector should be used. Specific types of connectors for parallel SCSI devices were developed by vendors over time. Connectors for serial SCSI devices have diversified into different families for each type of serial SCSI protocol. See the SCSI connector article for a more detailed description. Although parallel SCSI-1 devices typically used bulky Blue Ribbon Amphenol connectors, and SCSI-2 devices typically used Mini-D connectors, it is not correct to refer to these as "SCSI-1" and "SCSI-2" connectors. One valid rule is that connectors for wide SCSI buses have more pins and wires