Green’s Dictionary of Slang

1. (orig. US) to sound a whistle as a signal, e.g. at the end of a working day; also as n., the sounding of such a whistle.

1925		S. O’Casey Juno and the Paycock Act I: The blow up for dinner is at one.
1950		S. Murphy Stone Mad (1966) 186: When the Gaffer shouts ‘Blow-up’ at one o’clock, the atmosphere improves slightly.
1988		McGill Dict. of Kiwi Sl. 16/1: blow up referee blowing whistle to stop play for an infringement.
2003		McGill Reed Dict. of N.Z. Sl. [as cit. 1988].

2. (Aus.) to hail, to call out to.

1918

Aussie (France) 9 Dec. 1/1: A ‘bushed’ Digger blew up to a stationary car containing a Fourth Divvy Staff Colonel, one night at Cappy, with: ‘Hey, Nugget, can you tell me the way to Divvy Headquarters?’.

3. to wake up, to start work.

1938

X. Herbert Capricornia (1939) 212: Right-o lads — blow up! [...] Feller wage-slaves — blow up and do your dooty!

4. (US campus) to call a mobile phone repeatedly; of the phone, to ring repeatedly.

2003		Eble Campus Sl. Nov. 1: blow up – for a cell phone to ring: Her phone was blowing up the entire time I was with her.
2017		A. De Bruyn Escaping the Amazon 242: In the taxi, as expected, Jimmy began blowing up my phone. After the tenth attempt, I finally answered.
2022		A. Kirzman Giuliani xiv: [M]y phone started blowing up each night after my stories aired.