1. code (SSR) "The number assigned to a particular multiple pulse reply signal transmitted by a transponder in Mode A or Mode C."
2. SSR code "A four-digit octal number received from the aircraft transponder when it is interrogated by a secondary surveillance radar (SSR)"
1. ICAO, Official definition, PANS-ATM Procedures for Air Navigation Services — Air Traffic Management [Doc 4444] 2001, 14th ed. (Amdt 3, 29/06/2004)
2. Transport Canada (2010) Glossary for Pilots and Air Traffic Services Personnel,