What is wrong with bifurcation? I think that this is the right word in this context as this is the word often used to describe video and audio signals.

See for example http://en.wikipedia.org/wiki/MPEG-4_Part_3

and there are many more examples.

Assuming "Se debe emplear" refers to a 'video signal splitter' mentioned earlier in the source text (i.e. we already know that's what we're talking about), then the same expression cannot be used again later in the sentence. You need a term denoting the points where these splitters are needed in the network topography.

'branch' or 'spur' (or even 'tap') would be suitable.

Se debe emplear en todas las **bifurcaciones de la señal de video**..."
-->
"(A splitter) must be used at every spur in the video signal network."

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Note added at 1 hr (2008-02-05 12:53:59 GMT)
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Your less techie 'commercial' readers might be happier with 'branch'.

Son elementos reactivos (inductancia y capacitancia), normalmente instalados en cajitas pequeñas, para hacer bifurcar la señal, por ejemplo para dos televisores. There are many reactive splitters for different signal frecuencies, these are specifically for video. If "lo que se debe emplear.." is a resistive load, then this is definitely it.

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Note added at 2 hrs (2008-02-05 13:59:16 GMT)
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Neil, as always it depends on the rest of the text. You'd have to decide what it is that must always be used at every place where the signal splits, and then take it from there. It's doubtful that "un bifurcador se debe emplear en cada bifurcación ....". And a splitter is far from techie, anyone who has owned audio/video equipment knows what a splitter is, without knowing how the thing works.