Baird's original design used a electro-mechanical interface: a spinning disc with a spiral of precisely-placed holes served both as camera and as receiver. The camera/transmitter placed one or more photocells in front of the frame, and the receiver backlit an identically-proportioned disc with a small neon bulb with replicated the pulses recorded by the photocells. This "disc" system was used in the earliest public broadcasts of television in the early 1930's, during which home viewers -- "lookers-in" as they were called -- could tune to the high end of the radio band and receive remarkably clear pictures in the tiny window of their sets. The pictures were only 30 lines in resolution, but image captures and a few surviving off-air recordings show a distinct and recognizable images of human faces. The aspect ration of these broadcast was tall and narrow -- 3:7 -- which was designed to capture the presenter's upper body, a system one of the BBC's engineers quippingly called "head and shoulders."
And what we see in Things to Come is indeed a very tall and narrow aspect ratio. Wells's original treatment also refers on several occasions to the televisor's "disc," though in the final production design no discs are seen, and instead of a close-up of a disc with the outline of Cabal's head and shoulders, we're shown what looks like a filmstrip moving along a table. The screens in the film are of various sizes, including a small one in a translucent frame mounted on wheels, which we see Cabal pushing aside on his desk, disgusted with what he "sees" (a clever shot which eliminated the need of showing the screen image). Showing the same image on devices of many sizes, and at several locations, certainly prefigures our age of desktops, laptops, tablets, and smartphones, a connection that goes unremarked by the disc's commentator, David Kalat.
And interestingly, if Wells was fascinated by Baird's invention, Baird had grown up as an avid fan of Wells, whom he jokingly referred to as his 'demigod.' By chance, in 1931, both were passengers on the US-bound Aquitania, and Baird was able to finally meet his hero, though by his account the conversation was awkward, and did not touch on television; the snapshot above shows their meeting. It's hard to imagine a more resonant pairing -- the inventor of television with the pre-eminent writer of science fiction -- and yet what comes through most clearly is that both were, as Baird remarked, 'poor vulgar creatures' -- mere mortals who, as things turned out, would not live to see the ultimate forms the technologies they imagined would take.