What is "esatap"

In computing, eSATAp (also known as Power over eSATA, Power eSATA, eSATA/USB Combo, eSATA USB Hybrid Port/EUHP) is a combination connection for external storage devices. An eSATA or USB device can be plugged into an eSATAp port. The socket has keyed cutouts for both types of device to ensure that a connector can only be plugged in the right way.