is still electromagnetic, as is optical.
electromagnetic field, wave, signal, whatever is naught but a bundle
of longitudinal EM waves plus their dynamics (Whittaker 1903 + 1904).
The frequency band does not matter -- anything from ELF to optical to
gammas and beyond.
the CSR is just another set of longitudinal EM waves plus dynamics,
every normal magnetic, electrical, or electromagnetic wave, signal,
and field appears to be a vast superhighway for it to travel through
or reside in.
one is inserted into the superhighway inside the EM signals (makes no
difference what bandwidth) recorded on the CD-ROM. Optical,
whatever, makes no difference.
when you replicate the CD-ROM, you replicate all the interior stuff.
You produce another CD-ROM with another resident CSR identical to the
just communicate with that one using LWs, and have it go whever you
wish. All mass, etc. is filled with EM fields, waves, and
potentials -- so the interior of mass is a vast superhighway or set of
superhighways for CSRs to travel through with great ease.