8 analog I/O on DB25 connectors, 8 AES digital I/O (DB25 breakout), MIDI I/O, wordclock I/O. Comes stock with an empty card slot, which can be fitted with one of these 16-channel cards: LT-FW (FireWire 400), LT-USB (USB 2), LT-HD (Pro Tools HD), LT-ADAT (Optical), LT-MADI.