Communication of some length (4)

I believe the answer is:

wire

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'communication' is the definition.
(wire is a kind of communication)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for wire that I've seen before include "Thin strip of metal, may be barbed" , "Telegram about the fencing material" , "Electrical connector" , "Flex" , "Flexible strands of metal" .)

I've seen this clue in the Evening Standard.

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