Unless they are like Burnaby which uses a disposition code to tell dispatch the conclusion of a call, ie : Fire extinguished, MVA, Public assist etc, than I am going to say the Enterphone code of an apartment. I could be wrong , I have never heard Abby or Mission or Chilliw, use disposistion codes, I will listen today to all three depts and try to see if this is something new. EHS always asks for code to get in front door of apartments, and because they download certain types of calls that FD can handle (which is many time closer), thats my edumucated guess.