A parametric communications modeler would be best. What I mean by that is that it should understand packet length and transmission time and draw the diagram accordingly.

I am currently developing a custom communications protocol for an industrial device and need to generate a bunch of these. At the moment, for lack of a better tool, I am using AutoCAD. I could use SolidWorks sketches and figure out a way to use equations to make them parametric, but it just won't work well to produce these illustrations.

The ideal tool would, for example, understand that it takes, say, 1 ms to transmit a byte and 12 ms to transmit a 12 byte packet and, say, 4 ms for the ACK response packet and draw the graph accordingly. If I redesign the packet and it becomes 10 bytes rather than 12, the graph should update automatically.

If I had the time I might create something like this myself, but the most intelligent path is to see if this sort of thing exists.

[0] https://www.researchgate.net/figure/C-C-communication-network-timing-diagram_fig10_228713284