DEC VT520

Connectors

The readside of the terminal features:

Interface with Linux getty

Getty is configured in /etc/inittab.

ttyS0::respawn:/sbin/getty -h ttyS0 9600 vt520

The terminal also needs to be configured to match these settings. Mismatches will very quickly result in garbed character output. The configuration menu on the terminal can be entered via Alt+PrtScr (The sysRq key combination).

Status line

The status line is a reserved line at the bottom of the terminal display, which works in a similar fashion like the window title for graphical terminal emulators. The terminfo database defines the tsl and fsl (to/from status line) sequences, but it seems as of 2020, they contain garbage:

tsl=\E[2$~\E[1$}\E[%i%p1%d`
fsl=\E[0$}

The resulting behavior was that the status line always got appended to, including the stray backtick from the end of the string. This made the status line really non-useful. I worked out a fixed version that goes like this:

tsl=\E[2$~\E[1$}\E[G\E[K
fsl=\E[0$}        

The terminfo database can be edited by exporting it via infocmp vt520, saving and editing it as a file and then compile it back into the database via tic vt520.src.