používají analogovou techniku a mají šířku pásma větší než 2,5 GHz,
Performing "optical amplification" using praseodymium-doped fluoride fibre amplifiers (PDFFA); c. Employing coherent optical transmission or coherent optical detection techniques (also called optical heterodyne or homodyne techniques); d. Employing wavelength division multiplexing techniques exceeding 8 optical carriers in a single optical window; or e. Employing analogue techniques and having a bandwidth exceeding 2,5 GHz;