DHD Audio Audio 52-7224AXC Analog I/O Module, 18/24dBu4 analog line inputs, 18 or 24dBu, electronically balanced, 24 bit4 analog line outputs, 18 or 24dBu, electronically balanced, 24 bit4 GPI, isolated, 4 GPO isolatedreplaces 52-7222A and 52-7223A