To get ready, he made a breakout board for 32-channel analog multiplexer device he wants to use. He put the project out on Hackaday.io and also has a video tutorial you can see below. There are ...

PXI is an acronym for PCI eXtensions for Instrumentation (PXI). A multiplexer circuit combines two or more digital signals onto a single line, using time-division multiplexing. The signals can be ...

Eventually there was no more room for additional wire. The invention of the vacuum tube, plus amplifiers and oscillators, enabled telco engineers to develop frequency division multiplexing.