Modes
See also: Aviation transponder interrogation modesMode 1 – provides 2-digit 5-bit mission code. (military only – cockpit selectable)
Mode 2 – provides 4-digit octal unit code. (military only – set on ground for fighters, can be changed in flight by transport aircraft)
Mode 3/A – provides a 4-digit octal identification code for the aircraft, assigned by the air traffic controller. (military and civilian)
Mode 4 – provides a 3-pulse reply to crypto coded challenge. (military only)
Mode 5 – provides a cryptographically secured version of Mode S and ADS-B GPS position. (military only) Mode 5 is divided into two levels. Both are crypto-secure with Enhanced encryption, Spread Spectrum Modulation, and Time of Day Authentication. Level 1 is similar to Mode 4 information but enhanced with an Aircraft Unique PIN. Level 2 is the same as Mode 5 level one but includes additional information such as Aircraft Position and Other Attributes.
Mode C – provides 4-digit octal code for aircraft's pressure altitude. (military and civilian)
Mode S – provides multiple information formats to a selective interrogation. Typically aircraft are assigned a unique 24-bit Mode S address. The Mode S address is partitioned and a group of address ranges are allocated to each country. Some countries change the assigned address for security reasons, and thus it might not be a unique address. (military and civilian)
- Notes
Modes 4 and 5 are designated for use by US ARMY, USAF, USN, and NATO forces.
Read more about this topic: Identification Friend Or Foe
Famous quotes containing the word modes:
“Heaven is large, and affords space for all modes of love and fortitude. Why should we be busybodies and superserviceable?”
—Ralph Waldo Emerson (1803–1882)
“Without any extraordinary effort of genius, I have discovered that nature was the same three thousand years ago as at present; that men were but men then as well as now; that modes and customs vary often, but that human nature is always the same. And I can no more suppose, that men were better, braver, or wiser, fifteen hundred or three thousand years ago, than I can suppose that the animals or vegetables were better than they are now.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)
“my brain
Worked with a dim and undetermined sense
Of unknown modes of being; o’er my thoughts
There hung a darkness, call it solitude
Or blank desertion.”
—William Wordsworth (1770–1850)