Squawk box and Speaker unit

Squawk box noun - The loudspeaker on an intercom or public address system.

Speaker unit and squawk box are semantically related. In some cases you can use "Speaker unit" instead a noun phrase "Squawk box".

Speaker unit noun - Electro-acoustic transducer that converts electrical signals into sounds loud enough to be heard at a distance.

Squawk box and speaker unit are semantically related. Sometimes you can replace phrase "Squawk box" with "Speaker unit", this phrases are similar.