The PHCC system allows you to connect up to 1024 boolean (on/off) inputs. This should be sufficient for most simbuilder's needs (but no all as I've heard :-)
This allows you to connect for example:
- MCP/Autopilot panel
- MIP (main instrument panel)
- circuit breakers
These inputs are arranged in a matrix. The matrix consists of eight columns and 128 rows. The rows are organized in 16 groups of 8 rows. This translates into 16 keymatrix daughterboards with each 64 inputs (arranged as an 8x8 matrix).