How do cable lines on telephone poles transmit and receive data along thousands of houses and not get interference?
In: Engineering
They can’t. Nowadays most are converted to digital (or a series of ones and zeros that represent the analog signal), and these signals are transmitted. When they get close to where they want to go, and the result of the interference would be small, they’re converted back to analog.
As /u/doyouseeit suggests, older lines would multiplex the signals together. Think of it like the radio in your car. The signals from each station are separated, and interference will be minimal. There is still interference, but it could be minimal with large separation between the signals. (Note this also implies an expensive wire to transmit the data that could give you enough separation between the signals.)
There is a whole branch of mathematics related to this, called communication theory. It was really established when a smart man called Claude Shannon took work started by Harry Nyquist and really proved a lot of unexpected things. Although that work was originally complicated, many cases of the math have largely been solved to a degree that you can take off-the-shelf solutions, and guarantee communication to whatever reliability standard you want.
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