应答机代码列表

以下列表展示了在各个国家或地区用于特定目的之航空器应答机代码和代码范围。传统来说，每个国家都通过自己的方案分配转发器代码，不同国家的代码几乎没有共同点。该列表由于历史兴趣而被保留。
飞行员通常需要将空中交通管制分配的代码应用于特定的航班。有时，国家可能会指定在没有分配代码的情况下使用的通用代码。此类通用代码在该国的航空情报手册或航行资料汇编中指定。对于国际民用航空组织（ICAO）定义的特定情况，有标准应答器代码。
下列列表中，以红色显示的应答器代码仅用于紧急情况，例如飞机劫持、无线电通信故障及機上發生緊急狀況等。
| 代码 | 国家/地区 | 用途 |
| --- | --- | --- |
| 0000 | 欧洲 | Non-discrete mode A code; shall not be used. |
| 0000 | 英国 | Mode C or other SSR failure |
| 0000 | 美国 | Should never be assigned. |
| 0000 | 美国 | Military intercept code. |
| 0000 | 美国 | Internal ARTCC subsets assigned by Enroute Safety and Operations Support. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 0021 | 德国 | (VFR squawk code for airspace 5,000英尺（1,500） and below prior to 15 March 2007 when replaced by the international 7000 code for VFR traffic.) |
| 0022 | 德国 | (VFR squawk code for airspace above 5,000英尺（1,500） – prior to 15 March 2007 when replaced by the international 7000 code for VFR traffic.) |
| 0025 | 德国 | Parachute dropping in progress.[來源請求] |
| 0033 | 英国 | Parachute dropping in progress. |
| 0041–0057 | 比利时 | Assigned for VFR traffic under Flight Information Services (BXL FIC).[來源請求] |
| 0100 | 澳大利亚 | Flights operating at aerodromes (in lieu of codes 1200, 2000 or 3000 when assigned by ATC or noted in the Enroute Supplement). |
| 0100–0400 | 美国 | Allocated to Service Area Operations for assignment for use by Terminal/CERAP/industry/unique purpose/experimental activities. |
| 0100–0700 | 美国 | Non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2. |
| 0100–0700 | 美国 | Also for use in oceanic airspace unless another code is assigned by ATC. |
| 0500, 0600, 0700 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 1000 | 加拿大 | Instrument Flight Rules (IFR) flight below 18,000 ft ASL when no other code has been assigned. |
| 1000 | ICAO | Non-discrete mode A code reserved use in mode S radar/ADS-B environment where the aircraft identification will be used to correlate the flight plan instead of the mode A code. |
| 1000 | 美国 | Used exclusively by ADS-B aircraft to inhibit mode 3A transmission. |
| 1000 | 美国 | Non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2. Also for use in oceanic airspace unless another code is assigned by ATC (美国). |
| 1000 | 美国 | External ARTCC subset. (Block of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 1100 | 美国 | Non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2. Also for use in oceanic airspace unless another code is assigned by ATC. |
| 1100 | 美国 | External ARTCC subset. (Block of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 1200 | 澳大利亚 | Civil VFR flights in class E or G airspace. |
| 1200 | 加拿大, 美国 | Visual flight rules (VFR) flight standard squawk code used in North American airspace when no other has been assigned or is applicable. |
| 1201 | 美国 | Assigned via FAR 93.95 for use by VFR aircraft in the immediate vicinity of LAX. |
| 1201 | 美国 | (Visual flight rules (VFR) glider operations for gliders not in contact with ATC, through February 2012.) |
| 1202 | 美国 | 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. |
| 1203–1272 | 美国 | Discrete 1200 series codes unless otherwise allocated (for example, 1255), designated for DVFR aircraft and only assigned by a flight service station. |
| 1255 | 美国 | Aircraft not in contact with an ATC facility while enroute to/from or within the designated fire fighting area(s). |
| 1273–1275 | 美国 | Calibration Performance Monitoring Equipment (CPME) "Parrot" transponders. |
| 1276 | 美国 | Air Defense Identification Zone (ADIZ) penetration when unable to establish communication with ATC or aeronautical facility. |
| 1277 | 美国 | VFR aircraft which fly authorized SAR missions for the 美国AF or 美国CG while enroute to/from or within the designated search area. |
| 1300 | 美国 | Non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2. Also for use in oceanic airspace, unless another code is assigned by ATC. |
| 1300 | 美国 | External ARTCC subset. (Block of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 1400 | 加拿大 | VFR flight above 12,500' ASL when no other code has been assigned. |
| 1400 | 日本 | VFR flight above 10,000' MSL when no other code has been assigned.[來源請求] |
| 1400 | 美国 | External ARTCC subset. (Block of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 1500 | 美国 | Non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2. Also for use in oceanic airspace unless another code is assigned by ATC. |
| 1500 | 美国 | External ARTCC subset. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 1600, 1700 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 2000 | 澳大利亚 | Civil IFR flights in class G airspace. |
| 2000 | 加拿大 | Uncontrolled IFR at or above 18,000 ft MSL. |
| 2000 | ICAO countries | Code squawked when entering a secondary surveillance radar (SSR) area from a non-SSR 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 | 美国 | Non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2. Also for use in oceanic airspace unless another code is assigned by ATC. |
| 2000 | 美国 | External ARTCC subset. (Block of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 2100 | 澳大利亚 | Ground testing by aircraft maintenance staff. |
| 2100 | 美国 | Non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2. |
| 2100 | 美国 | Also for use in oceanic airspace unless another code is assigned by ATC. |
| 2100 | 美国 | External ARTCC subset. (Block of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 2200, 2300, 2400 | 美国 | Non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2. |
| 2200, 2300, 2400 | 美国 | Also for use in oceanic airspace unless another code is assigned by ATC. |
| 2200, 2300, 2400 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 2500, 2600, 2700 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 3000 | 澳大利亚 | Civil flights in classes A, C and D airspace, or IFR flights in class E airspace. |
| 3000 | 美国 | External ARTCC subset. (Block of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 3100, 3200, 3300, 3400, 3500, 3600, 3700 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 4000 | 澳大利亚 | Civil flights not involved in special operations or SAR, operating in class G airspace in excess of 15NM offshore. |
| 4000 | 美国 | Aircraft on a VFR Military Training Route or requiring frequent or rapid changes in altitude. |
| 4000 | 美国 | Non-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2. |
| 4000 | 美国 | Also for use in oceanic airspace unless another code is assigned by ATC. |
| 4000 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 4100 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 4200, 4300 | 美国 | Internal ARTCC subsets assigned by Enroute Safety and Operations Support. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 4400–4477 | 美国 | Reserved for use by SR-71, YF-12, U-2, B-57, pressure suit flights, and aircraft operations above FL600. |
| 4401–4433 | 美国 | Reserved in accordance with FAA Order JO 7110.67 (Federal Law Enforcement). |
| 4434–4437 | 美国 | Weather reconnaissance, as appropriate. |
| 4440,4441 | 美国 | Operations above FL600 for Lockheed/NASA from Moffett Field. |
| 4442–4446 | 美国 | Operations above FL600 for Lockheed from Air Force Plant 42. |
| 4447–4452 | 美国 | Operations above FL600 for SR-71/U-2 operations from Edwards AFB. |
| 4453 | 美国 | High balloon operations: National Scientific Balloon Facility in Palestine, Texas; and other providers, some in international operations. |
| 4454–4465 | 美国 | Air Force operations above FL600 as designated in FAA Order 7610.4. |
| 4466–4477 | 美国 | Reserved in accordance with FAA Order JO 7110.67 (Federal Law Enforcement). |
| 4500, 4600, 4700 | 美国 | Internal ARTCC subsets assigned by Enroute Safety and Operations Support. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 5000 | 澳大利亚 | Aircraft flying on military operations. |
| 5000 | 美国, 加拿大 | Reserved for use by NORAD. |
| 5061–5062, 5100, 5200 | 美国 | Reserved for special use by Potomac TRACON. |
| 5100, 5200, 5300, 5500 | 美国 | Internal ARTCC subsets assigned by Enroute Safety and Operations Support. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 5100–5300 | 美国 | May be used by DOD aircraft beyond radar coverage but inside 美国 controlled airspace with coordination as appropriate with applicable Area Operations Directorate. |
| 5400 | 美国, 加拿大 | Reserved for use by NORAD. |
| 5600, 5700 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 6000 | 澳大利亚 | Military flights in class G airspace. |
| 6000 | 美国 | External ARTCC subset. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 6100 | 美国, 加拿大 | Reserved for use by NORAD. |
| 6200, 6300 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 6400 | 美国, 加拿大 | Reserved for use by NORAD. |
| 6500, 6600, 6700 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete 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 | 美国 | External ARTCC subset. (Block of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 7000 | 澳大利亚 | 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 | 英国 | Sudden military climb out from low-level operations. |
| 7004 | 英国 | Aerobatic and display code in some countries. |
| 7100, 7200, 7300 | 美国 | External ARTCC subsets. (Blocks of discrete codes except that xx00 is used as a non-discrete code after all discrete codes are assigned.) |
| 7100, 7200, 7300 | Switzerland | 7100 in Switzerland for SAR (REGA). |
| 7400 | 美国, 英国, 澳大利亚 | Unmanned aerial vehicle lost link. |
| 7500 | ICAO | 飞机被劫持 |
| 7501–7577 | 美国 | Reserved for use by Continental NORAD Region (CONR). |
| 7600 | ICAO | 飞机通讯故障 |
| 7601–7607 | 美国 | Reserved for special use by FAA. |
| 7610–7676 | 美国 | External ARTCC subset (block of discrete codes). |
| 7615 | 澳大利亚 | Civil flights engaged in littoral zone surveillance. |
| 7700 | ICAO | 飞机遭遇紧急情况 |
| 7701–7707 | 美国 | Reserved for special use by FAA. |
| 7710–7776 | 美国 | External ARTCC subset (block of discrete codes). |
| 7777 | 美国, 德国, 比利时, 荷兰 | Non-discrete code used by fixed test transponders (RABMs) to check correctness of radar stations (BITE). |
| 7777 | 美国 | DOD interceptor aircraft on active air-defense missions and operating without ATC clearance in accordance with FAA Order 7610.4. |