Beyond Electronics Corporation’s 2nd generation, seven slot, ¾_ATR Airborne Enclosure has been highly optimized for strength, light weight and reliability. It is available in conduction or convection cooled versions. The convection version can be customer configured to support conduction cooled boards in any combination of slots. The box features a very high strength machined aluminum design with interchangeable depth top and bottom covers for easy cable routing.


  • 8 Slots - seven 6U, VME64x, VMEbus slots plus one Power Supply Slot
  • Machined aluminum design with structural “ribbing” producing exceptional strength
  • Available in conduction or convection cooled versions with the same internal user area dimensions, making migrating to production painless and low cost
  • Modular plug-in power supply for easy maintenance
  • Intelligent system built in test with network and front panel reporting
  • “Deep” top and bottom covers available to provide additional cable routing or board space
  • EMI gasketed for quiet operation and low susceptibility
  • -40 to +85°C operation


The ¾_ATR is actually a high strength, light weight; enclosure designed around a number of physical sizes, bus interface and connection standards. The exterior of the box conforms to the standard ARINC404 size profile and utilizes the ARINC600 hold-downs. The volume of the box can be expanded by the addition of a deep top and/or bottom that can be used to accommodate cabling or additional electronics.

The card frame of the box was designed around Eurocard standards so can be easily modified to accept many popular embedded formats. Since the backplane is designed to be easily removed and modified, it can also be modified to support hybrid designs of mixed standards. The base unit accommodates 6U VME64x boards. The convection cooled version of the product has an added feature that arbitrary board slots can be user configured to provide cooling in support of conduction cooled boards. This is accomplished by the addition of aluminum cooling bars that are attached by screws to the card frame at the respective slot.

To support high powered add in boards such as DSPs and FPGA boards, the convection cooled box has a high altitude, high pressure, extended temperature, variable speed fan mounted in a plenum at the rear of the unit.

In the standard configuration, the fan draws air in from the rear of the unit and forces it across the boards to be exhausted through the three EMI filters at the front of the box. For applications requiring reversed air flow, the fan can be “flipped”. An optional rear adapter ring for scat tube or similar hook up is available. For applications desiring to convert an air cooled box to conduction cooled, solid panels are available to replace the EMI filter openings.

Power supplies for the unit are fully modular. They interface to the unit through a pair of airborne connectors with guide pins. All versions of the power supply are designed to operate in conduction cooled environments. Once the power supplies are plugged into their backplane slot, they are then screwed to the side panel of the box, insuring an adequate heat path. For convection cooled boxes, the mounting is the same, but the fan blowing over the back of the power supply and through some small channels provides an even greater thermal margin.

The ¾_ATR has a selection of three power supplies:

  • 250 Watt with a 16 – 32 Volt DC Input
  • 650 Watt with an autoranging AC input: 90 to 132 Volts and 180 to 264 Volts, 47 to 440 Hz
  • 650 Watt with a 18 – 36 Volt DC Input

All three power supplies have a built in test feature. However, the reporting of the 650 Watt units was enhanced to include not only front panel display but also an Ethernet interface for real time reporting of the box status.

The front panel display of the box is user configurable to display an hour meter function, system warnings, system temperature or a variety of other internal functions.

The family resemblance of the conduction and convection cooled box is more than coincidental. Every effort has been made to make the internal dimensions and mounting locations of the two box types identical. The primary reason for this is to allow customers, who want to migrate from a convection cooled to a conduction cooled solution to prototype their systems with convection cooled boards and then either convert their existing box to conduction cooled or migrate directly to the conduction cooled version of the box while retaining any custom work they may have done.

The front panel of the box can be factory cut to accommodate user connectors or can be easily removed and modified by a customer. 3D models and dimensional drawings are available for all customers to allow easy documentation of any modifications. The drawings are available in native Solid Works, STEP, pdf or any of a number of exported formats.

Convection Cooling Fan

  • 28 Volts DC +/- 10%
  • 3.45 Amps
  • 6000 RPM at free delivery
  • 424 CFM at free delivery

General Specifications

  • Air Filters EMI honeycomb with screen
  • Overall Dimensions 10.02” tall x 7.50” wide x 16.7” long
  • Mounting Standard ARINC 404A
  • Weight 17.5 lbs
  • Backplane 7-slot monolithic, ANSI/VITA 1.1-1997, VME64x

Environmental Specifications

  • Shock 40G ½ sine, 20 mS
  • Random Vibration 0.1g2/Hz 5-1000Hz
  • Sine Vibration 5g 32-2000Hz
  • Humidity 100% condensing
  • Operating Temperature -40C to +85C
  • Storage Temperature -55C to +100C


  • Datasheet in "pdf" format
  • Hardware User Manual (upon request)
  • Environmental Test Report (upon request)

Front panel: This box was configured as the “test mule” for repeated environmental testing looking for any possible design weakness. Nearly any arbitrary customer connector configuration is available at the time of manufacture.

Large Rear Panel Intake: the rear of the box is covered by a replaceable EMI filter and screen. The filter screen combination serves three purposes:

  • Provides EMI protection
  • Provides protection from vermin
  • Because of the angled design of the honeycomb, it also provides rain protection

Side view: This is again the “test mule” box showing the side air vents with their EMI screens. Additionally, it shows the deep bottom and standard top configuration.

Cut away view of the ATR

Ordering Information