external SATA (eSATA)

External SATA (eSATA) is a SATA interface for hard drives in external enclosures. Moving hard disk drives to external enclosures is a relatively simple and convenient way to increase the storage capacity ofpersonalcomputers. Alternatives for this are the USB interface or Firewire and also the SATA interface. For this purpose eSATA was developed.

The advantage of eSATA compared to the other solutions is the higher flexibility, since no protocol conversion takes place via a so-called bridge chip, which leads to performance losses.

Connector for external SATA connections (eSATA), Image: Seagate

Serial ATA transmits data on a thin cable in a serial format and thus achieves much higher data rates than parallel ATA, which uses ribbon cables. The external Serial ATA (SATA), eSATA, operates at data rates of 1.5 Gbit/s and differs from the internal SATA only in having more robust and better shielded connectors and cables to avoid electromagnetic interference( EMI).

Another small difference between the internal and external SATA is the minimum transfer voltage, which has been raised from 400 mV to 500 mV, while the receiver input voltage has been lowered to 240 mV.