The Custom IO module is part of the Adroit Custom bundle.
The module provides extensive input and output facilities for Custom Panel modules enabling them to communicate with other modules in various ways beyond the remote control of knobs, sliders and buttons.
Each Custom IO module provides 8 audio/CV inputs, 8 CV outputs, 8 pairs of configurable VCAs and MIDI input/and output facilities.
Up to four of these modules can be used at once. Use the BANK button to select a different bank (A, B, C or D) for each.
See https://adroitsynthesis.com/custom-io/ for details.