Each device has a specific data transfer rate that is either MBps (Megabytes per second), or Kbps (kilobits per second).
The following chart shows the maximum that these device's can go with the correct cable attached:
 
 

DEVICE

SPEED

ATA / IDE / EIDE / DMA / UDMA 16MBps to 33MBps FireWire 480MBps Parallel Port 115Kbps Serial Port 115Kbps SCSI Interface 80MBps to 640MBps USB 1.1 12MBps USB 2.0 480MBps 802.11b 11MBps  @ 2.4 Gigahertz 802.11a 54MBps  @ 5.0 Gigahertz 802.11g 54MBps  @ 2.4 Gigahertz