Green’s Dictionary of Slang

1. (US) of liquor sold in a bar, a brand typically sold only if the customer calls for it; also attrib.

1992		G.P. Pelecanos Firing Offense 70: The bartender [...] pulled my tab from between two rum bottles on the call rack.
1993		G.P. Pelecanos Nick’s Trip 41: I reached behind me to the second row of call, grabbed the black-labeled bottle of Jack, and poured him some sour mash.

2. see shout n.