On the blower

[GRIBBLEWORT]

Where does the phrase on the blower - for telephone - come from?

[horseman]

It is slang, British in origin and derives from the fact that a blower is a device that produces a current of air - often on to a fire to make it burn more fiercely (hot air) thus the telephone became a conduit of (usually) hot air. A blower is also slang for a braggart - and the same parallel applies.