IFF TRANSPONDER M424 - SELEX Elsag

System Type Function Intended Control Control Unit
Configuration installation means required
1- Data Bus M424 Transponder Avionics bay MIL-STD-1553B No
data Bus
M911 Optional Cockpit Front panel N.A.
Back up control Unit
for emergency
operation
2- Control Unit M424 Transponder Avionics bay Control Unit M910
OPERATION
M910 Control Unit Cockpit Front panel N.A.
The M424 IFF Transponder receives coded RF signals
from interrogators, decodes these signals and generates
coded RF replies. The M424 operates, iaw Stanag 4193,
in Modes MkXA and Mode S, i.e.:
• Modes 1, 2, 3/A and C (Stanag 4193 MkXA, Part I
and II)
• Mode S up to Level 3 (Stanag 4193 Part IV and ICAO
Annex 10)
and in addition, as an option adapted for the specific
application:
Secure Mode (crypto)
Secure Mode operation can be achieved through the use
of an external Crypto or, as an alternative, an internal
crypto module.
CONTROL
The flexibility of the Transponder allows a wide range of
operations and alternative solutions.
M910 CONTROL PANEL
• Provides full control of transponder operation
• Friendly display and keyboard design for system
initialization in pre-flight
• Conventional controls for recurrent in-flight operations
• Display of equipment status
• APX 100 compatible size
• Display
- NVG compatible lighting scheme i.a.w.
MIL-L-85762A, Type 1A
- Compatible with centralized background dimming
- Ambient Light Sensor
BACKUP EMERGENCY OPERATION
In the DataBus configuration, by means of the BCP.
DIVERSITY
The Transponder must be connected to a dual omnidirectional
antenna system to provide a full coverage above and
below the aircraft plane; in this case the Transponder
M424 performs the diversity operation in accordance
with STANAG 4193.
ALTIMETER
The M424 provides wide flexibility for the Altimeter
interface, since, in addition to the MIL1553, it
incorporates a discrete (Gillham) interface and an
additional serial A429 interface.
TIME OF DAY
The Transponder provides wide flexibility for the Time
of Day (ToD) interface, needed for certain applications,
since, in addition to the MIL 1553, it incorporates a
serial PTTI (GPS) interface and a serial A429 interface.
NAV DATA
The Transponder supports multiple standards, as input
interfaces, i.e. 1553 Bus, NMEA and A429.
CRYPTO VARIABLES FILL CONNECTOR
The Transponder is provided with a standard Fill
connector for Secure Mode supporting two selectable
standards:
• DS 101
• DS 102
TCAS AND MODE S
The M424 incorporates two bi-directional A429
interfaces, one to support the on-board TCAS function
(iaw A735A) and another dedicated interface for the
exchange of Full Level 2 or Level 3 Mode S data (function
provided by an external ADLP function)
Mode S operation:
Level 2 basic surveillance, as defined in Stanag 4193
Part IV, para. 5.1.1
Full Level 2 and Level 3, in accordance with Stanag
4193 Part IV and ICAO Annex 10; it will need the
implementation of the specific interface with the
aircraft for the exchange of data and controls (via the
1553 DataBus or the A429 bi-directional interface).
DISCRETE CONTROLS AND INDICATIONS
The M424 provides the necessary discrete interfaces
with the platform for the IFF functions, controls and
indications that are needed. Additional discrete
interfaces are provided in the equipment to allow, for the
MIL 1553 Bus configuration, redundant controls by
means of the Backup Control Panel (BCP).
DESIGN AND CONSTRUCTION
The M424 is a fully solid state equipment;
it makes extensive use of large scale programmable
components and state of art technologies, in order to
reduce volume and weight maximising the reliability.
Its structure is modular and includes a powerful BITE
(Power-up, Continuous and Initiated BIT).