Crosswordiee.com

% replaces any number of letters (la% - lake, lamp)_ replaces one letter (ca_ - car, cat)

Crossword clues for Call preceders:

MARCO: Call preceding "Polo!"
DIALTONES: Call preceders
IMHIT: Call preceding "Medic!"
ROBO: Cop or call preceder
MESS: Hall or call preceder
LET: Call that might precede "first service"