Can KiCAD import files from CADSTAR (ver 13)
I have never heared of cadstar.
I do know that there are scripts (in Python?) for importing Eagle projects in KiCad.
In the (almost finished) KiCad 5 these are integrated into KiCad itself.
But the scripts are also on the web / github.
If you have a lot and or big projects to convert and the cadstar files are ascii based, the Eagle scripts might give you a headstart if you want to write something yourself.
Cadstar is a lower end product by Zuken. My office used v10 in the past
The schematic and pcb files look like a structured mix of ascii text and binary strings
I haven’t heared of Zuken either but if it’s files are ascii based and have a reasonable structure then OP is almost halfway with re-using the Eagle scripts as a startpoint. Those scripts can ouput the KiCad format, so OP only has to read the cadstar file format.
Edit, Oops: “mix of ascii text and binary” missed that the first time. I’ll leave it to OP to decide if this would be a viable path for him.
Message for OP:
If there is no documentation available for cadstar file format, then open an “empty” project in a text editor first to get some clues about it’s strucrure. Then make a copy, add a few symbols & wires and compare the difference in a program which is made for comparing differences in text files.
meld is a quite usable Open Source project for this: