SATA vs. eSATA
SATA, or Serial ATA, is the standard device for connecting storage media, like hard drives and optical drives, to the motherboard. It replaced the older PATA standard that existed for a considerable length of time. It offers much faster data transfer speeds, of which people can’t seem to get enough. The eSATA, or External SATA, is a standard derivative of SATA, that is meant to be used with external hard drives. In this area, it competes with established standards like USB and Firewire, but has the advantage of being able to operate at faster speeds, when compared to the other two.
When it comes to the standards that were defined in SATA, eSATA does not change much at all, as they are still basically identical to each other. eSATA is just more forgiving, when it comes to the range of voltages, that is being sent and received across the cables. eSATA raised the transmit voltage, while lowering the threshold for receiving the signal. This is done to accommodate for the longer cable specification that is being used. The connectors of eSATA and SATA are not compatible with each other. This was probably done to avoid problems that might arise from the differing electrical characteristics that are being used.
Aside from the change in the shape of the connector that prevents SATA drives from being used with eSATA, the connectors and the cables themselves, also underwent changes to adapt them for external use. Additional shielding is used on the cables to prevent interference, and to comply with FCC standard. The contacts of the connectors have also been moved back a bit, to avoid the possibility of electrostatic discharge that might damage the internal circuitry of the drive or the motherboard. Lastly, the cables and connectors have been thoroughly tested to withstand the rigors of daily use. The eSATA connectors are tested to withstand at least 5000 insertions, while SATA connectors are tested for only 50. The connectors have also been redesigned so that it isn’t easily removed. This is very appropriate, as most external devices get knocked around pretty often.
Summary:
1. SATA is meant for use with internal drives while eSATA is meant to be used with external drives.
2. eSATA’s electrical characteristics are more forgiving compared to SATA.
3. SATA and eSATA connectors are not compatible with each other.
4. The eSATA cables and connectors are more thoroughly tested compared to SATA cables and connectors.