If the input/display device is genuinely a dumb terminal, you will need a PC and terminal emulation software, and a means of physically connecting the PC in the place of the terminal. This may be an RS232 serial interface. However, RS232 is/was one of the worst standards on the planet, because it tried to be all things to all men. So configuring a serial device of that generation is a nightmare, unless you have the documentation for the device you are emulating. As far as I remember, you need to set:
- data bits (7 or 8).
- stop bits ( 0, 1 or 2).
- parity bit (yes or no).
- bits per second (usually 300bps or 1200bps).
That is assuming:
- That the multi-user server has an ascii interface. If the server is a mini-computer that may be the case, but if it is an old IBM mainframe, it uses EBDIC rather than ASCII, so you would need a EBDIC terminal emulation card, which will probably require an old 8 bit ISA slot (which modern PCs lack).
Once you have all that sorted out, you need to use the facilities of the terminal emulation software to capture the screen output. Basically, it s not a trivial ask, and that assumes you have permission to connect a PC to the server in the first place!