I found my answer in another thread
"At this moment, Maxwell only supports frame-based DACs - The ether dream is an example of a non-USB DAC - it connects through ethernet - but I believe what you are asking about is frame-based verse continuous data DACs - Maxwell operates in the points domain and therefore it is not possible to use continuous data DACs like audio DACs."
I work a lot with oscilloscopes (not lasers) and mostly use soundcard (MOTU). For simple oscillographics there are no frames, but for few other implementations (Fontsynth, Rutt Etra clone) I do use frames - there is a beginning and end of what is drawn (i don't know if you mean the same thing). Some examples here (Also made with Max - mostly MSP, few jitter objects in Vector rescanning patch) :