Skip to content
Skip to main content

About this free course

Download this course

Share this free course

Digital communications
Digital communications

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.


Except for third party materials and otherwise stated (see terms and conditions [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] ), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence

Course image: Kohei314 in Flickr made available under Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence.

Grateful acknowledgement is made to the following source for permission to reproduce material within this unit:

Table 5: 'Nominal central wavelengths for CWDM’, ITU-T G.694.2 Prepublished Recommendation: Spectral Grids for WDM Applications: CWDM wavelength grid, International Telecommunication Union;

Table 6: 'Nominal central frequencies of the DWDM grid’, ITU-T G.691.1 Prepublished Recommendation: Spectral Grids for WDM Applications: DWDM frequency grid, International Telecommunication Union.

All other written material contained within this unit originated at the Open University

Don't miss out:

If reading this text has inspired you to learn more, you may be interested in joining the millions of people who discover our free learning resources and qualifications by visiting The Open University - openlearn/ free-courses