the personnel files and even the Lcars maps as well as the TOS medical bay among others are all readable. But when you look closely at the Ship computers most of the time (not counting the other times when sensor readings are written in numbers are letter based.) It is just a bunch of numbers in various boxes on the computer screen. While many will say that they are just random numbers put by the production staff, what is the in universe meaning of the numbers? It is important to point out that any cadet can read sensor readings and pre warp cultures with stolen UFP tech eventually crack the codes. The numbers also seem to be similar across cultures with Starfleet often able to decipher data from old and ancient computers. It wouldn't be to far off to conjuncture that every civilian in the UFP and beyond (among warp capable species) can read all the sensor data with ease. Thus in universe logic dictates that it shouldn’t be that hard for us to decipher the sensor data ourselves
With cadets coming from over 150 different cultures it would make sense for Starfleet to make their computer interfaces as easily read as possible.
One might readily assume that all language in the bright future depends utterly on the Universal Translator. There are way too many languages that one absolutely needs to learn to survive in the Starfleet environment (including those one has never heard before), so there is no point in even trying. Thus, people might be required to learn English, but they might not - the UT would handle it all even if Worf only ever spoke and understood Klingon, Bashir only ever spoke and understood Farsi, and O'Brien only ever spoke and understood a language of his own invention. The computer readouts could then be in any arbitrary language. And the chosen language of Starfleet is pure numbers. Timo Saloniemi
Placeholder text isn't meant to be taken literally. It's just a visual stand-in for something that's presumably more meaningful in-universe. That said, people who are trained in a field can see meaning in raw numbers or graphical symbols that would be meaningless to the layperson. For instance, police radio codes would sound like random numbers to the novice, but the officers have learned to recognize what the numbers mean. And an astrophysicist looking at a numerical readout of a radio signal such as the "Wow! signal" could recognize the information conveyed by a set of numbers and letters that would be gibberish to the rest of us.
Very advanced ways we can't possibly hope to understand. Like reading meaningful data from blinking coloured squares in The Original Series.
As an in-universe explanation, I would suggest that the numbers are representative of waveforms, particularly of the electromagnetic spectrum. The numerical format uses decimal numbers (1 to 9 and 0), spaces, dashes, and lines/paragraphs. These may be numerical representations of waveforms. Alternately, some sensor readings are just that: waveforms. Waveforms require cross-referencing to get the numbers, while just using numbers saves you time, but you have to pick the right numbers to interpret the data. A trained person could interpret the peaks and valleys rather quickly with numbers and a basic familiarity with the electromagnetic spectrum.
However, basically all pertinent data is in the form of number strings - not just waveforms or other sensor readings. Seemingly random numbers typically accompany every button on a screen, too, say. We could plead "special language or jargon" in each and every case separately (tactical console has two- or four-digit codes analogous to police codes, but also strings that indicate phaser energy levels or targeting probabilities or ammunition use statistics or target signature characteristics or coordinates or...). But while it might be humanely possible to read one of the above, reading all and never confusing them with the others is not. So I still claim the number strings are merely plain words or easy-to-read acronyms, just in a foreign language that the UT readily translates for the heroes. No real training required. Timo Saloniemi
Nice. It would be amazing if such technology were not abused. Imagine the implications of a technology that can make you see and hear whatever brainwave patterns conveyed.
It was a big improvement over the paper printouts 13 years prior to TOS: https://tos.trekcore.com/hd/albums/1x00hd/thecagehd0271.jpg