Two things connected in a way that cannot be modified by software
are hard wired. See also hard code
(but that applies to software, where this usually applies to hardware
Up until recently, making things "hard wired" was the only way to design electronics, until FPGAs and other on-board and self-programmable devices came into the market.
Note: Oops! It was just pointed out to me that some people write it as hardwired.