"Soup’s on!” is the timeless call that means that dinner’s ready and everyone should come to the table. The longer phrase --"soup’s on the table” ("soup’s on the stove” wouldn’t make any sense)—dates from at least the 1840s.
The shortened “Soup’s on!” appears to have been popularized by the nationally syndicated comic strip “The Gumps” in 1928, when the phrase was used often. The phrase “Soup’s on!” then began appearing frequently in newspaper headlines. The phrase is still used, although the call to the family meal isn’t heard as often today (when the family often eats at different times, rather than all together).
Soup’s on is a common term used to say, “Dinner’s ready.”
Wikipedia: The Gumps
The Gumps, a popular comic strip about a middle-class family, was created by Sidney Smith in 1917, launching a 42-year run in newspapers from February 12, 1917 until October 17, 1959.
The Gumps were utterly ordinary: chinless, bombastic blowhard Andy who is intimidated by his wife, Min (short for Minerva), their son Chester, rich Uncle Bim and their annoying maid Tilda. They had a cat called Hope and a dog called Buck. The idea was envisioned by Captain Joseph M. Patterson, editor and publisher of the Chicago Tribune, who was important in the early histories of Little Orphan Annie and other long-run comic strips. Patterson referred to the masses as “gumps” and thought a strip about the domestic lives of ordinary people and their ordinary happenings would appeal to the “gumps.” He hired Smith to write and draw the strip, and it was Smith who breathed life into the characters.
August 1842, Dublin University Magazine, pg. 145, col. 1:
“Your reverence has a minute and a-half yet; but the soup’s on the table.”
The Makings of a Big Leaguer
By Burt L. Standish
New York, NY: Barse & Hopkins
“Now the soup’s on the tablecloth!” he thought, as he slid into his coat and moved rapidly away.
By Maximilian Foster
Illustrated by Frederic Rodrigo Gruger
New York, NY: D. Appleton and Company
“Soup’s on!” said Minnie tersely;...
The Man on Horseback
By Achmed Abdullah
New York, NY: TheJames A. McCann Company
“The soup’s on the table!”
10 September 1928, Salt Lake Tribune (Salt Lake City, UT), The Gumps (comic), “Soup’s on Again,” pg. 18:
(Said by a person in the last panel—ed.)
8 October 1928, Salt Lake Tribune, “The Gumps” (comic), “Soup’s On!”, pg. 19:
(Said by a person in the second panel—ed.)
(Screamed by that same person in the third panel—ed.)
8 November 1928, Newark (OH) Advocate, “The Gumps” (comic), “Soup’s On!”, pg. 15:
(Shouted by a person in the third panel—ed.)
16 April 1930, Los Angeles (CA) Times, pg. 4:
SOUP’S ON, AND IT’S HOT! NOW HE’S ON—DOWNY COT
21 May 1930, Los Angeles (CA) Times, pg. 12:
“OH, HENRE-E-E. SOUP’S ON!”
Fresno and Kings Counties Plan Contest for Best Husband-Callers
Woman about Town:
By Allis McKay
New York, NY: Macmillan
... departed and left them alone in the twilight-filling room, and Skip, with an apron around his massive waist, appeared in the door and said, “Soup’s on.”
Flesh is Not Life
By Hilary Leighton Barth
Published by The Bruce Publishing Company
“She says soup’s on — and insisting as usual that we shouldn’t wait. Shall we talk vicious circle over our buffalo?”
By Cora Lovisa Brackett Brown, Rose Johnston Brown, Bob Brown, Robert Carlton Brown
Published by The Greystone Press
13 December 1949, Dallas (TX) Morning News, section 3, pg. 4:
If you are one of those fortunate souls who stroll on December evenings, and whose olfactories are in order, no doubt you know it is soup season.
By Karin Kelly
Illustrated by George Overlie
Published by Lerner Pubns Co (L)
By Nancy Baggett, Glick Baggett, Ruth Glick
New York, NY: Macmillan
Sixty Hearty Soups You Can Stand Your Spoon In
By Janet Lembke, William (PHT) Nash, Adrian C. (PHT) Stanley
Published by Lyons Press
Soul-Satisfying Recipes from Your Favorite Cookbook Authors and Chefs
By Leslie Jonath
Photographs by Frankie Frankeny
Published by Chronicle Books