Apparatus

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sensors Mode-S transponder

ABC123

ICAO 24-bit transponder address · allocated to United States

Hex
ABC123
Octal
52740443
Decimal
11,256,099
Country
US
No current signal · last broadcast 17h ago
Flights observed
177
Distinct callsigns
13
Country
US
Last broadcast
17h ago

Last known position

Most recent position reported by Mode-S ABC123.

Country allocation

The ICAO 24-bit address ABC123 falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.

Callsign history 13 distinct

Callsign Airline Flights Last seen
PSARS - 76 2026-07-17
6 - 37 2026-07-14
TEST01Z - 20 2026-07-15
DECLH - 11 2026-07-14
PSEFT - 5 2026-06-15
R8065 - 2 2026-05-30
R5556 - 2 2026-04-26
N733T - 2 2026-07-17
DOCH08 - 2 2026-05-13
00000000 - 2 2026-04-16
R5382 Malta Air Charter 1 2026-05-22
AB12CD34 - 1 2026-04-23
1200 - 1 2026-07-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-17 N733T - Jul 17, 12:50 UTCJul 17, 14:00 UTC1h 10m
2026-07-17 PSARS - Jul 17, 11:04 UTCJul 17, 11:20 UTC15m
2026-07-16 PSARS - Jul 16, 17:40 UTCJul 16, 17:54 UTC15m
2026-07-16 PSARS - Jul 16, 11:05 UTCJul 16, 11:30 UTC25m
2026-07-16 1200 - Jul 16, 01:25 UTCJul 16, 02:20 UTC55m
2026-07-15 TEST01Z - Jul 15, 20:35 UTCJul 15, 20:40 UTC5m
2026-07-15 TEST01Z - Jul 15, 20:15 UTCJul 15, 20:25 UTC10m
2026-07-15 PSARS - Jul 15, 17:45 UTCJul 15, 18:00 UTC15m
2026-07-15 PSARS - Jul 15, 11:05 UTCJul 15, 11:25 UTC20m
2026-07-14 TEST01Z - Jul 14, 19:55 UTCJul 14, 20:05 UTC10m
2026-07-14 TEST01Z - Jul 14, 19:40 UTCJul 14, 19:45 UTC5m
2026-07-14 TEST01Z - Jul 14, 19:15 UTCJul 14, 19:20 UTC5m
2026-07-14 TEST01Z - Jul 14, 19:00 UTCJul 14, 19:05 UTC5m
2026-07-14 TEST01Z - Jul 14, 18:45 UTCJul 14, 18:55 UTC10m
2026-07-14 TEST01Z - Jul 14, 18:25 UTCJul 14, 18:40 UTC15m
2026-07-14 TEST01Z - Jul 14, 18:10 UTCJul 14, 18:20 UTC10m
2026-07-14 TEST01Z - Jul 14, 17:55 UTCJul 14, 18:05 UTC10m
2026-07-14 TEST01Z - Jul 14, 17:15 UTCJul 14, 17:50 UTC35m
2026-07-14 TEST01Z - Jul 14, 16:55 UTCJul 14, 17:10 UTC15m
2026-07-14 DECLH - Jul 14, 07:30 UTCJul 14, 08:35 UTC1h 5m
2026-07-14 6 - Jul 14, 01:30 UTCJul 14, 02:35 UTC1h 5m
2026-07-10 PSARS - Jul 10, 16:20 UTCJul 10, 16:35 UTC15m
2026-07-10 PSARS - Jul 10, 14:05 UTCJul 10, 14:25 UTC20m
2026-07-10 DECLH - Jul 10, 09:55 UTCJul 10, 10:55 UTC1h 0m
2026-07-10 DECLH - Jul 10, 07:45 UTCJul 10, 08:40 UTC55m
2026-07-09 DECLH - Jul 9, 16:25 UTCJul 9, 17:10 UTC45m
2026-07-09 DECLH - Jul 9, 14:00 UTCJul 9, 15:00 UTC1h 0m
2026-07-08 PSARS - Jul 8, 13:25 UTCJul 8, 14:10 UTC45m
2026-07-08 PSARS - Jul 8, 10:00 UTCJul 8, 10:35 UTC35m
2026-07-07 PSARS - Jul 7, 19:25 UTCJul 7, 20:10 UTC45m
2026-07-07 DECLH - Jul 7, 15:25 UTCJul 7, 16:10 UTC45m
2026-07-07 6 - Jul 7, 02:55 UTCJul 7, 03:05 UTC10m
2026-07-06 PSARS - Jul 6, 11:05 UTCJul 6, 11:20 UTC15m
2026-07-06 6 - Jul 6, 02:25 UTCJul 6, 02:35 UTC10m
2026-07-03 PSARS - Jul 3, 17:50 UTCJul 3, 18:05 UTC15m
2026-07-03 PSARS - Jul 3, 14:50 UTCJul 3, 15:00 UTC10m
2026-07-03 PSARS - Jul 3, 11:05 UTCJul 3, 12:25 UTC1h 20m
2026-07-02 TEST01Z - Jul 2, 18:30 UTCJul 2, 18:40 UTC10m
2026-07-02 6 - Jul 2, 04:40 UTCJul 2, 05:10 UTC30m
2026-07-02 6 - Jul 2, 01:20 UTCJul 2, 01:50 UTC30m
2026-06-30 PSARS - Jun 30, 10:25 UTCJun 30, 11:15 UTC50m
2026-06-30 6 - Jun 30, 00:39 UTCJun 30, 02:05 UTC1h 26m
2026-06-28 PSARS - Jun 28, 19:40 UTCJun 28, 19:49 UTC10m
2026-06-28 PSARS - Jun 28, 13:14 UTCJun 28, 13:25 UTC10m
2026-06-26 6 - Jun 26, 07:14 UTCJun 26, 07:24 UTC10m
2026-06-25 PSARS - Jun 25, 18:19 UTCJun 25, 18:29 UTC10m
2026-06-24 6 - Jun 24, 01:44 UTCJun 24, 02:00 UTC15m
2026-06-23 PSARS - Jun 23, 17:54 UTCJun 23, 18:20 UTC25m
2026-06-23 TEST01Z - Jun 23, 16:59 UTCJun 23, 17:20 UTC20m
2026-06-23 6 - Jun 23, 01:45 UTCJun 23, 02:20 UTC35m

About Mode-S

A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.

Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.

Mode-S ABC123 frequently asked

What is Mode-S code ABC123?
ABC123 is an ICAO 24-bit transponder address. Allocated to United States.
Where is Mode-S ABC123 registered?
Mode-S code ABC123 is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is ABC123 broadcasting right now?
No active broadcast right now. Last signal was 17h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex ABC123, octal 52740443, decimal 11,256,099.
What flights does ABC123 operate?
Mode-S ABC123 has broadcast 13 distinct callsigns, including PSARS, 6, TEST01Z, DECLH, PSEFT.