What are data multiplexers?

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For instance, I work for the government and in their IT closet I see these big racks that are carrying multiple fiber lines which terminate into this box that says:

Nokia 1665 DMX which is apparently something called a “data multiplexer.”

I did some research but I still don’t quite understand what they do. Are they for combining data, tv, and phone signals together from the ISP?

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Anonymous 0 Comments

In my world a ‘multiplexer’ is a device that splits the light spectrum on a fiber optic cable into multiple smaller wavelengths, or ‘colors’. I mean, they are literally colors but mostly outside of the visible spectrum. What that allows us to do is take one fiber optic cable and make 100 or so separate connections.

If I use the whole spectrum for the connection, I would need one fiber strand to send data, and one fiber to recieve data. This is basic networking, a CAT6 ethernet works similarly, a number of pins send, a number of pins recieve. With a multiplexer, I could give you only one strand and you could have a send recieve pair (or multiples) on the same strand.

ISPs are interesting, I work for a US based on, we use something called hybrid coax. A coaxial cable is a cable that has a solid copper core and then a mesh copper that surrounds it that is separated by a medium that prevents crosstalk. A hybrid coax adds a fiber optic line to the middle of it. If you deliver TV over the copper, then the internet is delivered over the fiber and that fiber would have to be split into waves.

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