As further discussed in Bohm and Hiley on “active information“, McLuhan, prompted in different ways in the late 1940s by Innis, Havelock, Giedion and the cybernetics work at MIT of Wiener and Deutsch, began to investigate how literature and contemporary science might illuminate each other. Here are a texts from 1951 to 1955 discussing this notion:

the electron valve you [Norbert Wiener] describe [in The Human Use Of Human Beings]  represents a principle discovered in 1870 by Arthur Rimbaud and applied to poetry and painting since that time. Your account of the uses of the vacuum tube in heavy industry is an exact description of the poetic techniques of Joyce and Eliot in constructing their works. Their use of allusion as situational analogy effects an enormous amplification of power from small units, at the same time that it permits an unrivalled precision. Their stripping of rhetoric and statement corresponds to your observation that “it is no longer necessary to control a process at high-energy-levels by a mechanism in which the important details of control are carried out at these levels.” Stephane Mallarmé made this observation about his own poetic technique in 1885. (McLuhan to Norbert Wiener,  March 28, 1951, Norbert Wiener Papers M.I.T.)

I’m interested in such analogies with modern poetry as that provided by the vacuum tube. The latter can tap a huge reservoir of electrical energy, picking it up as a very weak impulse. Then it can shape it and amplify it to major intensity. Technique of allusion as you use it (situational analogies) seems comparable to this type of circuit. Allusion not as ornament but as precise means of making available total energy of any previous situation or culture. Shaping and amplifying it for current use. (McLuhan to Pound, June 12, 1951, Letters 224)

As a vacuum tube is used to shape and control vast reservoirs of electric power, the artist can manipulate the low current of casual words, rhythms, and resonances to evoke the primal harmonies of existence or to recall the dead. (Joyce, Mallarmé and the Press, 1954)

The technique of an Eliot poem is a direct application of the method of the popular radio-tube grid circuit to the shaping and control of the charge of meaning. An Eliot poem is one instance of a direct means of experiencing, under conditions of artistic control, the ordinary awareness and culture of contemporary man. (Counterblast, 1954)

If print was the mechanization of the handicraft of writing, the telephone was the electrification of speech itself, a big step past the telegraph. Gramophone and movie were merely the mechanization of speech and gesture. But the radio and TV were not just the electrification of speech and gesture but the electronification of the entire range of human personal expressiveness. With electronification the flow is taken out of the wire and into the vacuum tube circuit, which confers freedom and flexibility such as are in metaphor and in words themselves. (Historical Approach to the Media, 1955)

The simplest way to get at Joyce’s technique in language, as well as to see its relation to TV, is to consider the principle of the electronic tube. The paradox of the electronic tube is that it is the means of breaking the conductor in an electric circuit. The tube permits the electrons to escape from the wire that ordinarily conveys them. But the tube controls the  conditions of escape. It liberates electrons from the wire but it provides a new context in which they can be repatterned. The cathode inside the tube is one end of the broken conductor and the anode is the other. The anode attracts and receives the billions of electrons that are “boiled” off the surface of the cathode. When a tube is connected into an alternating-current circuit, the anode is positive during half of each cycle. During the half cycle when the anode is negative, electrons cannot reach the anode. It is this characteristic of an electronic tube which enables it to act as a rectifier, changing alternating currents into direct current.
The grid is the controlling or “valve” electrode of the tube. It is located between the cathode and the anode in the path of the electrons. By voltage control the grid acts as trigger for the electronic flow. Grid bias blocking electronic flow is recentralized by signal voltage. Signal voltage is a trigger that releases full flow of current through the tube. But this flow stops when anode voltage becomes negative. Cycle then repeats. The load of current on this cycle is a motor.
When current is too weak for direct flow, it can, in a vacuum tube, be used as signal voltage on the grid of the tube. Then every variation in the shape of the wave will be faithfully reproduced in the output wave of the tube. Thus a tiny amount of energy can be exactly controlled or stepped up instantly to very high potentials.
Now metaphor has always had the character of the cathode-anode circuit, and the human ear has always been a grid, mesh, or, as Joyce calls it in Finnegans Wake, Earwicker. But Joyce was the first artist to make these aspects of language and communication explicit. In so doing, he applied the principles of electronics to the whole history of culture. The entire cyclic body of Finnegans Wake is suspended between a predicate and a subject. The cathode-anode aspect of metaphor and language Joyce first extended to syntax. He took the charge of meaning out of the wire of direct statement into the vacuum-tube of the self-contained poetic drama of his “all nights newsery reel.” (FW 489)
Metaphor means a carrying across. All speech is metaphoric because any oral sound is a gesture towards externalizing an inner gesture of the mind. The auditory situation is a carrying across from a silent situation. Writing is metaphor for sound. It translates, or metamorphizes the audible into the visual. There is necessarily discontinuity in metaphor. There has to be a leap from one situation to another. (‘Radio and Television vs. The ABCED-Minded’, Explorations 5, 1955)