Dial up modems. Loved the noise, tried to find it as my message alert a way back, just to piss people off!
They are the dominant "crisp" brand here in Australia. Frank Smith emigrated here and set up the Aust branch of the company. (Despite Australians using the term "chips" for crisps, Smith's called their product crisps until as late as 2003. They are now labelled as Smith's Chips. As of 2010–2011, portions contained in "large" bags of Smith's Snackfood products have diminished, down from 200g to 175g (approximately equal to the previous 1975 large size of 6½oz) - Wikipedia. Range and prices: https://shop.coles.com.au/a/a-national/everything/search/smiths chips