Patent ID: 8559817

Claim:
A communication system that comprises: a communication unit with a first part ( 1 ) and a number of a second part ( 2 ), where each second part ( 2 ) is arranged to be located at an end-user location, where the first part ( 1 ) is common for the number of the said second parts ( 2 ), where the first part and each second part comprise a laser (Tx, 17 ), where each second part is connected to the first part by a fiber optic cable ( 3 ) and a frequency filter ( 4 ; 12 , 13 ), and where the first part ( 1 ) and each second part ( 2 ) are arranged to exchange information by laser light, where each one of the second parts ( 2 ) comprises a tunable laser ( 6 ), where the first part ( 1 ) is arranged to analyze light received from each second part ( 2 ), where the first part ( 1 ) is arranged to transmit information to the second part ( 2 ) while the first part is receiving light from the second part, where the said information contains information for the second part ( 2 ) to adjust, where required, a frequency or wavelength of the second part ( 2 ), and where the second part ( 2 ) is thereby arranged to change said frequency or wavelength, each of the lasers ( 6 ) is not bound to a certain wavelength/frequency, and each of the lasers ( 6 ) is arranged to change between different wavelengths/frequencies by control currents led to the laser, wherein each of said lasers ( 6 ) is arranged to transmit on different wavelengths/frequencies, corresponding to different channels, light emitted from the second part ( 2 ) and being received by the first part ( 1 ) is analyzed by the first part ( 1 ), and the first part ( 1 ) is arranged to transmit said information, regarding adjustment of the wavelength/frequency received while the first part ( 1 ) is receiving the light emitted from the second part ( 2 ).