It should be noted that the Space Marines do not make use of cybernetic Mind Impulse Units when linking with their Power Armour. Instead, their enhanced physiology equips them with a biological means to interface with it -- the gene-seed organ known as the Black Carapace. The Black Carapace allows the Space Marine to make maximum use of his Power Armour's capabilities. It is unknown if the Black Carapace allows a Space Marine to establish neural links with other forms of machinery.