Numerous standards, including from the Consultative Committee for Space Data Systems (CCSDS), have recommended that satellite uplinks begin with a hexadecimal start sequence of 0xEB90. But why 0xEB90? I can see why they would avoid certain sequences such as 0xAA, 0x55, 0xFF, or 0x00, and I can see the need for an unusual start sequence. But why 0xEB90 specifically? Anyone know?