As your needs grow or change, you can easily add analog or digital inputs and outputs by installing an expansion card
You have a choice of 3 cards. The HD I/O AD option adds 8 analog inputs. The HD I/O DA option adds 8 analog outputs. And the HD I/O Digital option adds 8 I/O channels each for AES/EBU (supports single-wire and dual-wire with a 192 kHz sample rate), TDIF, and ADAT (supports S/MUX II and IV)