Its deeper than youre capable of imagining. Its just black magic coupled with applied science. They weren't developed in tandem, there was a breakthrough in PCB and electrical engineering, while there was also a new breakthrough/understanding of sigil magic using shit similar to pic related. There were some engineers into black magic and witchcraft, and they rolled with it and started making deeper breakthroughs in electrical engineering and electronics. Basically trapping demons, or invoking certain powers or abilities with the sigils designed into the PCBs.