A series of two or three musical notes, used as an auditory alert over a radio or radio-paging system to indicate that a particular fire company, district, or territory is dispatched to service on a particular incident
Wikipedia, The Free Encyclopedia, Glossary of firefighting equipment, Wikimedia Foundation, http://en.wikipedia.org/wiki/Glossary_of_firefight ing_equipment, CA, USA 2012. (Fr Srvc - Amer) {509}