Kind of off-topic -- but I still remember laughing when I read about how the oil industry was using "IP over mud" between the drill tip and a receiver. Apparent

Kind of off-topic -- but I still remember laughing when I read about how the oil industry was using "IP over mud" between the drill tip and a receiver. Apparently, the temperatures won't allow typical electronics to survive in the environments where a drill tip operates. So they used the drill tip itself to vibrate the mud around the drill. I don't know if they still use anything like that.