These options for the HDSP 9632 and HDSPe AIO are analog expansion boards, designed as bracket with 4 stereo TRS jacks each. AI4S-192 AIO provides four servo-balanced inputs, AO4S-192 AIO provides four servo-balanced outputs. With this a maximum of 6 (including the stereo I/O of the card) inputs and/or outputs can be achieved.
The converters offer the same performance as the on-board stereo analog I/O of the HDSPe AIO: up to 192 kHz, balanced connection and the choice of three different reference levels, selected in the Settings dialog.
Both modules can be used single or in combination. The display of the channels in TotalMix changes accordingly.
Note: AI4S-192 and AO4S-192 (without the suffix AIO) do work only with the HDSP 9632. The current Expansion Boards with the suffix AIO work with both cards.
More information could be found in the manuals: