Side-by-Side Comparison
Avionics & Flight Operations
ARINC 429 Data Bus vs. Transponder Squawk Codes
Comparing 2 standards across 13 specifications. 13 key differences identified.
Comparing:
ARINC 429 Data Bus
Transponder Squawk Codes
The ARINC 429 standard is the predominant two-wire differential data bus used across commercial and transport avionics, transmitting 32-bit digital words over a single transmitter / multi-receiver shielded twisted pair using Bipolar Return-to-Zero (BPRZ) modulation.
Air traffic control secondary surveillance radar (SSR) interrogates airborne transponders to receive 4-digit octal Squawk Codes (digits 0–7), with internationally reserved codes for emergency conditions: 7500 (Hijacking), 7600 (Radio Failure), and 7700 (General Emergency).
Specification Comparison Table
13 Parameters| Parameter / Spec | ||
|---|---|---|
|
Specification
|
Aeronautical Radio, Inc. (ARINC) 429 Mark 33 Digital Information Transfer System | — |
|
Physical Topology
|
Single transmitter, up to 20 receivers (simplex broadcast, point-to-point) | — |
|
Wiring Medium
|
78 Ω shielded twisted pair cable | — |
|
Low-Speed Baud Rate
|
12.5 kbps (bit duration 80 μs) | — |
|
High-Speed Baud Rate
|
100.0 kbps (bit duration 10 μs) | — |
|
Modulation Scheme
|
Bipolar Return-to-Zero (BPRZ: +10V High, -10V Low, 0V Null) | — |
|
Standard Authority
|
— | ICAO Annex 10 / FAA Order JO 7110.65 |
|
Digit Base
|
— | 4-digit Octal (0000 to 7777, providing 4,096 distinct discrete codes) |
|
Emergency Hijack Code
|
— | 7500 (Unlawful Interference) |
|
Emergency Comms Failure
|
— | 7600 (Lost Radio Communications) |
|
General Emergency Code
|
— | 7700 (Mayday / Immediate In-flight Emergency) |
|
VFR Standard (US/Canada)
|
— | 1200 |
|
VFR Standard (Europe/ICAO)
|
— | 7000 |