以下列表展示了在各個國家或地區用於特定目的之航空器應答機程式碼和程式碼範圍。傳統來說，每個國家都透過自己的方案分配轉發器程式碼，不同國家的程式碼幾乎沒有共同點。該列表由於歷史興趣而被保留。 飛行員通常需要將空中交通管制分配的程式碼應用於特定的航班。有時，國家可能會指定在沒有分配程式碼的情況下使用的通用程式碼。此類通用程式碼在該國的航空情報手冊或航行資料彙編中指定。對於國際民用航空組織（ICAO）定義的特定情況，有標準應答器程式碼。 下列列表中，以紅色顯示的應答器程式碼僅用於緊急情況，例如飛機劫持、無線電通訊故障及機上發生緊急狀況等。 程式碼 國家 地區 用途 0000 歐洲 Nondiscrete mode A code shall not be used 0000 英國 Mode C or other SSR failure 0000 美國 Should never be assigned 0000 美國 Military intercept code 0000 美國 Internal ARTCC subsets assigned by Enroute Safety and Operations Support Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 0021 德國 VFR squawk code for airspace and below prior to 15 March 2007 when replaced by the international 7000 code for VFR traffic 0022 德國 VFR squawk code for airspace above prior to 15 March 2007 when replaced by the international 7000 code for VFR traffic 0025 德國 Parachute dropping in progress 0033 英國 Parachute dropping in progress 00410057 比利時 Assigned for VFR traffic under Flight Information Services BXL FIC 0100 澳大利亞 Flights operating at aerodromes in lieu of codes 1200 2000 or 3000 when assigned by ATC or noted in the Enroute Supplement 01000400 美國 Allocated to Service Area Operations for assignment for use by TerminalCERAPindustryunique purposeexperimental activities 01000700 美國 Nondiscrete code assignments in accordance with FAA Order JO 711065 52 01000700 美國 Also for use in oceanic airspace unless another code is assigned by ATC 0500 0600 0700 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 1000 加拿大 Instrument Flight Rules IFR flight below 18000 ft ASL when no other code has been assigned 1000 ICAO Nondiscrete mode A code reserved use in mode S radarADSB environment where the aircraft identification will be used to correlate the flight plan instead of the mode A code 1000 美國 Used exclusively by ADSB aircraft to inhibit mode 3A transmission 1000 美國 Nondiscrete code assignments in accordance with FAA Order JO 711065 52 Also for use in oceanic airspace unless another code is assigned by ATC 美國 1000 美國 External ARTCC subset Block of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 1100 美國 Nondiscrete code assignments in accordance with FAA Order JO 711065 52 Also for use in oceanic airspace unless another code is assigned by ATC 1100 美國 External ARTCC subset Block of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 1200 澳大利亞 Civil VFR flights in class E or G airspace 1200 加拿大，美國 Visual flight rules VFR flight standard squawk code used in North American airspace when no other has been assigned or is applicable 1201 美國 Assigned via FAR 9395 for use by VFR aircraft in the immediate vicinity of LAX 1201 美國 Visual flight rules VFR glider operations for gliders not in contact with ATC through February 2012 1202 美國 Visual flight rules VFR glider operations for gliders not in contact with ATC effective February 2012 1202 加拿大 Visual flight rules VFR glider operations for gliders not in contact with ATC effective February 2017 12031272 美國 Discrete 1200 series codes unless otherwise allocated for example 1255 designated for DVFR aircraft and only assigned by a flight service station 1255 美國 Aircraft not in contact with an ATC facility while enroute tofrom or within the designated fire fighting area s 12731275 美國 Calibration Performance Monitoring Equipment CPME Parrot transponders 1276 美國 Air Defense Identification Zone ADIZ penetration when unable to establish communication with ATC or aeronautical facility 1277 美國 VFR aircraft which fly authorized SAR missions for the 美國 AF or 美國 CG while enroute tofrom or within the designated search area 1300 美國 Nondiscrete code assignments in accordance with FAA Order JO 711065 52 Also for use in oceanic airspace unless another code is assigned by ATC 1300 美國 External ARTCC subset Block of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 1400 加拿大 VFR flight above 12500 ASL when no other code has been assigned 1400 日本 VFR flight above 10000 MSL when no other code has been assigned 1400 美國 External ARTCC subset Block of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 1500 美國 Nondiscrete code assignments in accordance with FAA Order JO 711065 52 Also for use in oceanic airspace unless another code is assigned by ATC 1500 美國 External ARTCC subset Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 1600 1700 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 2000 澳大利亞 Civil IFR flights in class G airspace 2000 加拿大 Uncontrolled IFR at or above 18000 ft MSL 2000 ICAO countries Code squawked when entering a secondary surveillance radar SSR area from a nonSSR area used as uncontrolled IFR flight squawk code 2000 EASA countries Code that pilot shall set in the absence of ATS instructions related to code setting unless when not receiving air traffic services 2000 美國 Nondiscrete code assignments in accordance with FAA Order JO 711065 52 Also for use in oceanic airspace unless another code is assigned by ATC 2000 美國 External ARTCC subset Block of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 2100 澳大利亞 Ground testing by aircraft maintenance staff 2100 美國 Nondiscrete code assignments in accordance with FAA Order JO 711065 52 2100 美國 Also for use in oceanic airspace unless another code is assigned by ATC 2100 美國 External ARTCC subset Block of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 2200 2300 2400 美國 Nondiscrete code assignments in accordance with FAA Order JO 711065 52 2200 2300 2400 美國 Also for use in oceanic airspace unless another code is assigned by ATC 2200 2300 2400 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 2500 2600 2700 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 3000 澳大利亞 Civil flights in classes A C and D airspace or IFR flights in class E airspace 3000 美國 External ARTCC subset Block of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 3100 3200 3300 3400 3500 3600 3700 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 4000 澳大利亞 Civil flights not involved in special operations or SAR operating in class G airspace in excess of 15NM offshore 4000 美國 Aircraft on a VFR Military Training Route or requiring frequent or rapid changes in altitude 4000 美國 Nondiscrete code assignments in accordance with FAA Order JO 711065 52 4000 美國 Also for use in oceanic airspace unless another code is assigned by ATC 4000 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 4100 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 4200 4300 美國 Internal ARTCC subsets assigned by Enroute Safety and Operations Support Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 44004477 美國 Reserved for use by SR71 YF12 U2 B57 pressure suit flights and aircraft operations above FL600 44014433 美國 Reserved in accordance with FAA Order JO 711067 Federal Law Enforcement 44344437 美國 Weather reconnaissance as appropriate 44404441 美國 Operations above FL600 for LockheedNASA from Moffett Field 44424446 美國 Operations above FL600 for Lockheed from Air Force Plant 42 44474452 美國 Operations above FL600 for SR71U2 operations from Edwards AFB 4453 美國 High balloon operations National Scientific Balloon Facility in Palestine Texas and other providers some in international operations 44544465 美國 Air Force operations above FL600 as designated in FAA Order 76104 44664477 美國 Reserved in accordance with FAA Order JO 711067 Federal Law Enforcement 4500 4600 4700 美國 Internal ARTCC subsets assigned by Enroute Safety and Operations Support Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 5000 澳大利亞 Aircraft flying on military operations 5000 美國，加拿大 Reserved for use by NORAD 50615062 5100 5200 美國 Reserved for special use by Potomac TRACON 5100 5200 5300 5500 美國 Internal ARTCC subsets assigned by Enroute Safety and Operations Support Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 51005300 美國 May be used by DOD aircraft beyond radar coverage but inside 美國 controlled airspace with coordination as appropriate with applicable Area Operations Directorate 5400 美國，加拿大 Reserved for use by NORAD 5600 5700 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 6000 澳大利亞 Military flights in class G airspace 6000 美國 External ARTCC subset Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 6100 美國，加拿大 Reserved for use by NORAD 6200 6300 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 6400 美國，加拿大 Reserved for use by NORAD 6500 6600 6700 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 7000 ICAO VFR standard squawk code when no other code has been assigned 7000 EASA countries Code that pilot shall set when not receiving air traffic services unless otherwise prescribed by the competent authority 7000 美國 External ARTCC subset Block of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 7000 澳大利亞 Unmanned aerial vehicle in all classes of airspace and when instructed to enable transponder 7001 France Used in some countries to identify VFR traffic 7001 英國 Sudden military climb out from lowlevel operations 7004 英國 Aerobatic and display code in some countries 7100 7200 7300 美國 External ARTCC subsets Blocks of discrete codes except that xx00 is used as a nondiscrete code after all discrete codes are assigned 7100 7200 7300 Switzerland 7100 in Switzerland for SAR REGA 7400 美國，英國，澳大利亞 Unmanned aerial vehicle lost linkAustralian AIP ENR 16 para 646 7500 ICAO 飛機被劫持 75017577 美國 Reserved for use by Continental NORAD Region CONR 7600 ICAO 飛機通訊故障 76017607 美國 Reserved for special use by FAA 76107676 美國 External ARTCC subset block of discrete codes 7615 澳大利亞 Civil flights engaged in littoral zone surveillance 7700 ICAO 飛機遭遇緊急情況 77017707 美國 Reserved for special use by FAA 77107776 美國 External ARTCC subset block of discrete codes 7777 美國，德國，比利時，荷蘭 Nondiscrete code used by fixed test transponders RABMs to check correctness of radar stations BITE 7777 美國 DOD interceptor aircraft on active airdefense missions and operating without ATC clearance in accordance with FAA Order 76104 參考資料 Category 航空電子學 Category 編碼 Category 航空程式碼列表