switchboard vs plugboard

switchboard and plugboard both are nouns.

Word	Noun	Adjective	Verb	Adverb
switchboard	Yes	No	No	No
plugboard	Yes	No	No	No

As nouns, switchboard and plugboard are synonyms defined as:

switchboard and plugboard: telephone central where circuits are completed with patchcords

Other synonyms of switchboard include patchboard.

switchboard (noun)	plugboard (noun)
telephone central where circuits are completed with patchcords	telephone central where circuits are completed with patchcords