Data Exchange between Calc and Maxima CAS

I rarely use Maxima and am not an expert at all.
However I recently wanted to check numerical results I got using Calc in a convoluted way. For this purpose I needed to create a large matrix with complex numbers as elements in Maxima from data generated in Calc. Typing was not an option.
Well, doing some additional preparation in Calc and then using the clipboard, I managed this, and also to get back a result to Calc (needing some post-processing).
Is there a kind of “interface” which can automate such a task?
(It might also be of interest to use GnuPlot graphics made with Maxima in LibreOffice.)