MODE S Transponder
BXP6401 series
Compact Line/Surveillance

The BXP6401 is a compact and lightweight single block Mode-S transponder. It is certified according to ETSO-2C112a (Level 2 es) and is suited for VFR and IFR operations up to 50.000 feet. It is available as Class 1 (BXP6401-1-(01)) as well as Class 2 (BXP6401-2-(01)) variant.
The Mode S ICAO address and additional fixed data are stored in a separate address module AM6400-1-(01), which is plugged on to the transponder and remains in the aircraft when the transponder is exchanged. This allows easy replacement without the need for reconfiguration. The BXP6401 is designed for panel mounting and fits into a 2 ¼ inch cut out. A remote controlled version is also available.
Panel inscription and sunlight readable display can be illuminated and dimmed for night operation. The display shows the actual settings.
The range of power supply voltage and the low power consumption make this transponder suitable for a wide range of aircraft. The transponder is prepared for the connection of blind encoders from different manufacturers. The blind encoder can be connected to the transponder by a serial or a parallel interface.
The BXP6401 is a Form and Fit replacement for the ATC4401 as the dimensions are the same and the main connector has the same pin assignment.
Technical data:
Supply voltage: | 10.0 V to 33.0 V DC |
Current consumption: Typical, without illum. | 0.43 A at 14 V 0.25 A at 28 V |
Standby | 0.22 A at 14 V 0.14 A at 28 V |
Power-up time: | 2 sec. (internal self–test) |
Ext. Fuse protection: | 5 A slow-blow |
Operating temperature: | -20°C to +55°C (short-time +70°C) |
Operating altitude: | ≤50.000 ft (BXP6401-1-(01)) ≤15.000 ft (BXP6401-2-(01)) |
MODE S | Level 2 es - extended squitter - surveillance identifier |
Vibration resistance in accordance with EUROCAE/RTCA ED-14D/DO-160D | Cat .S. Curve M Cat .U. Curve G |
Humidity in accordance with EUROCACE/RTCA ED-14D/DO-160-D | Cat. A / + 50°C 95%, 48 h |
Interfaces | Serial and parallel Altimeter Avionics data link processor |
Certification: | ETSO-2C112a. EASA.21O.322 |
Dimensions: | 61.3 x 61.3 x 205 cm (H x W x D) |
Receiver data:
Receive frequency: | 1030 MHz ± 0.2 MHz |
Sensitivity (MTL): | -74 dBm +/- 3 dB |
Selectivity: | ± 15 MHz > 40 dB ± 25 MHz > 60 dB |
Dynamic range: | ≥ 60 dB |
Side lobe suppression | 3-pulse method (A/C) P5 (Mode S) |
Nominal impedance | 50Ω |
Transmitter data:
Transmit frequency: | 1090 MHz ± 1 MHz |
Transmitter type: | Solid state |
Transmit power: | ≥250 W (BXP6401-1-(01)) ≥160 W (BXP6401-2-(01)) |
Reply rate limitation: | 500...12000 replies/sec. configurable |
Nominal output: | 50Ω |
Weight: | approx. 0.8 kg |
Control Unit CU6401-1-(01)
Operating temperature | |
-20°C to +55°C (short time +70°C) | |
Dimensions: | 61 x 61 x 65 mm (H x W x D) |
Weight Remote Transponder BXP6402-1R-(01) Class 1 Remote Transponder BXP6402-2R-(01) Class 2 | approx. 0.2 kg |
Operating temperature: | -20°C to +55°C (short-time +70°C) |
Dimensions: | 61 x 61 x 215 mm (H x W x D) |
Weight with address module | approx. 0.7 kg |
Remote controlled versions available:

