Question: I have looked around, but cannot seem to find out why. On SATA drives (2.5 and 3″), there are variable lengths to the copper contacts on both the data and power ports on the drives. These variations do not exist on an mSATA.
Is there a reason why these variable lengths are on all SATA plugs?
Answer: The longer pins are ground lines (“GND”)…
Data:
Power:
Ground lines are slightly longer than data/power lines on connectors that are intended to be regularly plugged/unplugged (especially in the case of hot-swap capable interfaces, like SATA) to ensure that the ground lines are being connected before any data/power lines are. ?This helps prevent electrical discharge into the device when attaching/removing it.
mSATA is an internal, clamp-down, ‘permanent’ connector type, so it’s not intended to be “plugged” and “unplugged” regularly (by end users), and definitely not while the power is on. 🙂