Each box delivers 24 input channels and 24 output channels. Depending on the unit this will be available in AES/EBU format on D sub connectors or on Toslink connectors for ADAT compatible connection. This is in adition to 64 channels of MADI I/O on the Alpha-Link MADI-AX and Alpha-Link MADI-SX.
The above figures apply when operating at up to 48 kHz. At 88.2 or 96 kHz, the I/O count is halved for ADAT and MADI but maintained for AES/EBU. MADI can operate in either 64 channel mode or 56 channel mode.