16-Channel Optocore I/O Expansion Card for YG2. 16In/16Out Audio Channels through console slot (miniYGDAI). 1 "Main" port to connect to YG2 card or YS2 card in cascade. 1 "Sub" port to connect to YS2 card in cascade for enlargement of audio channels up to 64In/64Out (32In/32Out at 96kHz). 1 RS232 port to upgrade internal logic.