Commercial, Embedded Avionics, Military

Product Focus: Databus and Connector Technologies  

By Jonathan Ray | June 1, 2013
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Companies providing support systems, such as data and video buses and connectors, are under pressure to address the shifting technology needs for new and older aircraft. Industry demands for greater bandwidth and size, weight and power (SWaP) use reductions, for example, are sparking the growth of advanced network architecture and fiber optic technology on civil and military platforms. These are not new developments, but the growing complexity of the aircraft systems still can test providers’ ability to keep up with pace of technology change and craft solutions for the increasing diverse technology environment.

The pressure to boost data rates and reduce SWaP is driving the increased use of faster deterministic bus architectures, such as Avionics Full-Duplex Switched Ethernet (AFDX) or ARINC 664, Part 7, as “the main avionics backbone bus,” said David Mead, executive vice president and chief operating officer at Holt Integrated Circuits, based in Mission Viejo, Calif.

Developed by Airbus for the A380, the AFDX bus approach is increasingly being used to communicate data on new aircraft including Boeing 787. It is being deployed “on the current, largest commercial aircraft development, the COMAC C919,” said Steve Holder, sales director, avionics at GE Intelligent Platforms, a subsidiary of GE which is providing avionics to the C919 program.

With data rates of 100 Mbps, the Ethernet system leaves the older ARINC and military standards transmission rates, which reach as high as 1 Mbps, in the dust. Along with addressing the need for speed, the system also delivers weight savings as it requires less wiring than the older standards. The question, however, remains open as to how far AFDX or any other Ethernet system will go toward displacing the veteran ARINC 429 and MIL-STD-1553 technologies.

“The developments in networking speeds and bandwidths are becoming increasingly compelling … (but) because avionics systems are mission-critical, there’s an inherent conservatism in the industry and rightly so that favors proven technologies,” said Holder.

In addition, “integrating such advanced architectures down to the sensor level remains an expensive prospect, and we have seen that these applications continue to remain dominated by more traditional databus technologies, such as ARINC 429 and MIL-STD-1553,” said George Noh, Holt’s director of sales and marketing. In fact, “at the ‘box’ level, there is still a growing demand for ARINC 429 and MIL-STD-1553, both in new applications and retrofit.”

One sign that the situation remains in flux is the fact that 1553-based technology continues to draw interest in the civil market for functions demanding high levels of reliability, especially flight-critical applications, according to Mead. At the same time, AFDX is being used or looked at for use on military platforms, such as the F-16 and the Airbus A400M. So as it stands now, platforms are using and will continue a mix of technology standards.

Not to be left out, “there is (also) a growing interest in CAN (Controller Area Network bus),” said Anthony Murray, Holt’s director of business development. “We have seen our CAN products used in a whole slew of applications, including braking control, engine monitors, fuel quantity management, electronic flight bag interfaces and radios.”

All of this complexity has spurred the development of versatile technologies to address and, in some cases, bridge the different technology standards. With the growing use of CAN Bus, “we have seen a steady increase in the amount of enquiries for our HI-3200,” said Murray. The device “is capable of managing, storing and forwarding avionics data messages between eight ARINC 429 receive channels, four ARINC 429 transmit channels and a single CAN/ARINC 825 data bus.”

In March, Holt Integrated Circuits announced formal MIL-STD-1553 RT validation of its HI-6130/31 BC/MT/RT multi-terminal system. These devices provide a single-chip, 3.3V MIL-STD-1553 BC/MT/RT Terminal system, including dual transceivers, in surface-mount plastic packages.

Data Device Corp. (DDC), based in Bohemia, N.Y., offers its AceXtreme Bridge Device multi-IO converter that has two channels of 1553, 2 gigabit Ethernet ports and up to six programmable ARINC 429 channels. Alta Data Technologies offers protocol translators, including the eNet-1553 and eNet-429 products that, respectively, bridge the older standards and the Ethernet.

Vendors are also developing devices to address size, weight and power and make maximum use of cockpit real estate. GE Intelligent Platforms introduced this year its RAR15-XMC multi-protocol embeddable avionics module which combines MIL-STD-1553A/B Notice II and ARINC 429 network protocols on a XMC.0 mezzanine card.

“By combining multiple functionalities that were previously discrete on a single board, it provides the designer with precious additional space and weight not to mention budget,” Holder said.

Holt offers its HI-2130 device, which “integrates digital protocol, analog transceivers and passive transformers in a single 15mm x 15mm compact package the smallest component solution available on the market today” for 1553, said Mead. For ARINC 429, Holt has introduced products to “integrate lightning protection on-chip, significantly reducing the number of components used in a system.”

Meanwhile, research and development continues into faster optical technologies. While still providing older, upgraded 1553 technology largely for older aircraft, API Technologies is “putting focused effort now” into developing its Opto-fire, optical transceiver, said Bob Hunt, head of engineering at the company’s U.K.-based RF2M Division.

“Fundamentally, the aircraft flight controls are served adequately with the existing lower data rates,” Hunt said, but it is the “data collection and processing … (for) the video systems (including) image recognition” and the “radar systems being fitted to aircraft, such as Active Electronic Radar Scanning systems … that are demanding higher data rates.” Currently, Opto-fire handles data rates “at 2.5-gigabit per channel, four channel (bi-directional) device,” but API is already looking to boost that “to 10 gigabit per channel … (or) 40 gigabit receive and 40 gigabit transmit,” Hunt said.

“The company has completed “extensive testing” of the product “in full temperature, so it is minus 40 to plus 95C operational” and is slated to go through qualification this year for the MIL-PRF-38534 requirement.

The technology is targeted for use on satellites, land vehicles as well as aircraft. “It will be suited for both new … (and) retrofit applications at some point in time,” he said, adding “we’d like to think that this will be a suitable upgrade for he the Typhoon Eurofighter aircraft.” API is currently providing a slower, 20 Mbps optical transceiver for the Typhoon.

Meanwhile, the growing use of new, larger digital cockpit displays is boosting the use of ARINC 818 or Avionics Digital Video Bus. ARINC 818 is the main video interface for the new Rockwell Collins and Thales Head Up and Head down displays and is being used on a wide list of military platforms including the A400M, the F-18 and F-15 upgrades and the Boeing 787, A350XWB and C919, said Tim Keller, director of marketing at Great River Technology. The Albuquerque, N.M.-based company provides technology and support for ARINC 818 systems including HOTLink II systems.

“A serial protocol for moving high-speed, mission critical video and data,” the standard allows for “great commonality between commercial and military implementations.” Since it was released, the standard has expanded beyond providing “the connection between mission or video processors and cockpit displays … (and) is now also moving into sensors and cameras,” spurring the growth of the number of ARINC 818 connections on an aircraft, “which then brings in the necessity of other equipment like switches and video concentrators,” said Keller. “Additionally, the new large area displays used on some of the new aircraft are driving some changes to the specification,” he said, noting an ARINC 818-2 revision is underway and expected before year’s end.

For connector providers, the push for additional data speed has meant having to work more with lighter, more capable fiber optic technology. It has provided a “paradigm shift” for the industry, especially on the commercial side, and “the challenge for the industry … (has been) to remain agile,” as this technology changes and morphs, said Earle Olson, business development manager at TE Connectivity.

When it was first used on the Boeing 777, the fiber was 100/140 micron size, but “quickly that core size … became obsolete and was supplanted by 62.5 (micron) on the 787 and Airbus A380,” Olson said. Now as bandwidth increases, “what we are seeing emerging is a 50 micron OM3 to an OM4 (fiber),” Olson said. The changes have meant a boost in throughput and the flexibility of the technology. As it has changed, “fiber core vendors have done really good work in the science area to come up with cores that are bend-insensitive and that are good for long life especially for a long-lived aircraft.”

Both the military and commercial are making use of the technology with former using more single mode fiber, which has “far greater capacity and certainly speed” than multimode fiber commonly used on commercial platforms, Olson said.

The increased use of the technology is providing opportunities for connector vendors offering ARINC 801 fiber optics standard connector products, such as Radiall with its LuxCis connectors, which can operate and multimode or single mode. TE Connectivity ARINC 801 connectors are being used on Irvine, Calif.-based Lumexis’s fiber to the screen (FTTS) an offering the TE helped develop. The system has been or is slated to be deployed on different platforms including 737-800 and -900s as well as Airbus A330s for its latest customer Turkish Airlines. Lumexis is one of the few companies to use the fiber for the entire backbone.

Other vendors offer partial solutions often because of ongoing issues related to maintaining the systems. Maintenance remains the technology’s Achilles heel when it comes to its expanded use in the harsh environment of a cabin of commercial transport aircraft. Despite the gains in data speed and lower weight, operators have been leery of expanding its use because of the investment training and tools to properly care for the technology.

This issue has spurred industry action as SAE and ARINC committees are now “spending some time on expanded beam,” said Olson. A non-contact form connection, expanded beam technology provides key benefits with regard to taking fiber to the seat, according to Larry Paterson, associate technical fellow with the Boeing Engineering, Operations & Technology unit. “It eliminates the need for the microscopic inspection equipment to be on hand during maintenance and installation actions … greatly simplifies cleaning equipment requirements … (and) is more impervious to scratch, chips, pits.”

Meanwhile, there is also the question of defining the relationship between fiber and copper. “It’s never been about either/or; it has always been both because at some point you are converting from electro to optical version,” Olson said. The question is where that conversion takes place “either it is going to be at the chip level, on the board or it is going to be at the panel.”

One of the trends has been “as boxes get tighter, (developers) want to move that functionality up to the panel and possibly … process their boards copper and have a mezzanine mountable device on it,” he said. “In other words the connector (would be) right on a panel mounted box.” This setup could allow developers to make better use of the available real estate on the aircraft.

With the growth of these new technologies, connector vendors, including those not working with fiber optics, have had to address the increasing “noise” and challenges produced by the complexity. All the systems along with new materials on aircraft the use composites rather than metal have increased the need for filtered connectors to address the noise and EMI threats, said Dave Arthurs, product manager, specialty connectors at API Technologies.

The need to add capacitor type filtering on the connectors is often prompted by “upgrades to electronics in the box”, which cause “the generation of higher levels of magnetic interference,” or an “upgrade of specification of system to meet a new set of EMI requirements,” Arthurs said.

The current push to get smaller puts extra pressure on the designers of these technologies. “When you start going smaller and tighter center- to-center spacings on the pins, it starts affecting how much capacitance you can put in connector … at a given voltage, so it starts to push the limits of what is technically feasible ‘law of physics-wise’,” said Arthurs.

“We’re going to see more and more requirements for filtered connectors just because the electronics that is in these boxes is being upgraded in the clock speeds and the switching speeds that are much higher and cause a higher-level of susceptibility for EMI problems,” Arthurs said. With all the changes to boards and other devices, “the connector is the logical place to put that because … it is still there.”

“We of course do all the standard sizes of circular connectors… but we have also moved into smaller type connectors or what we call Mini-MIL Connectors which are 38999 style connectors but much smaller in size,” he said. “We have also moved filtering into the Micro D connectors” reflecting the drive smaller size devices and “have also gone into the filtered composite shell the plastic connector both filtered and unfiltered.”

Next month: Wire and Cable

Avionics Magazine’s Product Focus is a monthly feature that examines some of the latest trends in different market segments of the avionics industry. It does not represent a comprehensive survey of all companies and products in these markets. Avionics Product Focus Editor Ed McKenna can be contacted at [email protected].


Alta Data Technologies
Ametek Aerospace
Avionics Interface Technologies
Ballard Technology
Beta Transformer Technology Corp.
Carlisle Interconnect Technologies
Curtiss-Wright Controls
Data Device Corp.
Edgewater Computer Systems
Endicott Interconnect Tech.
Excalibur Systems
GE Intelligent Platforms
Great River Technology
Holt Integrated Circuits
Hytronics Corp.
ITT Interconnect Solutions
National Hybrid Inc.
North Atlantic Industries
Phoenix Logistics
PIC Wire & Cable
Positronic Industries
Raycom Electronics
Sanmina-SCI Technology
Sital Technology
TE Connectivity
Tech SAT GmbH
Tepro of Florida
Vector GmbH
Western Avionics Ltd.

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