For those of you brave souls that would like to read the county mutual aid plan, it is online at http://www.westchestergov.com/emergserv/EM...lanDec03-v5.pdf In appendix F, it says that your agency code is first, than 0 for command unit, than 1,2,3, etc for rank order, with 1 being the ranking officer. I don't know why county would have you change over to 11, 12, 13 when they were updating their CAD system. But again, we don't know why county does a lot of what they do.