Send a wire to my employer! (9)

I believe the answer is:

telegraph

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'send a wire' is the definition.
(thesaurus)

I cannot understand how the rest of the clue works.

(Other definitions for telegraph that I've seen before include "Signal" , "Means of communication" , "Messaging system" , "A scoreboard" , "Transmission (by wire on poles)" .)

I've seen this clue in The Telegraph.

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