Death, taxes, and 1553
The decades-old, 1-megabit-per-second MIL-STD 1553 databus is still the reliable choice in old and new avionics systems.
By John McHale
In what might be someday termed the golden age of high-tech obsolescence—when technologies and standards come and go faster and faster—one 30-plus-year old standard continues to thrive.
The MIL-STD 1553 databus, which was originally designed into military platforms during the 1970s, continues to find its way into the most advanced commercial and military avionics programs of the 21 century.
The first version of 1553 flew in 1973 on the U.S. Air Force F-16 Falcon jet fighter, followed by 1553a in 1978 on the U.S. Navy and Marine Corps F/A-18 Hornet jet fighter-bomber. The modern standard, 1553b, emerged in 1978.
Despite critics who claim it is too slow for today's network-centric environment it still represents a profitable market for many original equipment manufacturers (OEMs). The market is strong with 1553 continuing to be designed in on such applications as the F-35 Joint Strike Fighter, says Mike Hegarty, MIL-STD-1553 marketing manager for Data Device Corp. (DDC) in Bohemia, N.Y.
The 1553 also has one of the largest installed bases of any military network. Estimates place the number of aircraft worldwide with 1553 close to 30,000, and the total number of deployed 1553 terminals, including munitions, at close to 1 million.
Next-generation databuses such as Fibre Channel or Ethernet are being deployed on programs like the U.S. Air Force F-22, but one reason 1553 is still viable is that there is still no one universal solution, Hegarty says.
It is still ideal for box-to-box command and control applications. So many designers figure "why try to reinvent the wheel," Hegarty adds.
"1553 was here when I first started and that was 20 years ago," says Tony Jordan, director-standard products at Aeroflex in Colorado Springs, Colo. While Aeroflex may not be spending a lot of dollars in research and development for 1553, "It's still kind of a cash cow, you just throw a little hay on it now and then."
It has a strong legacy base and will most likely have a role in new space programs such as NASA's Crew Exploration Vehicle (CEV), Jordan says. It is a deterministic, reliable technology that may never die, he adds.
Aeroflex put out a low-power 3-volt MIL-STD-1553 transceiver based on Aeroflex's legacy 5-volt transceivers, the UT63M143 3-volt transceiver. "Customers have been requesting a drop-in compatible, industry-standard 3-volt transceiver to aid in their avionic and aerospace design for some time," Jordan says.
"It's really a dandy market," says Bill Schuh, vice president of sales and marketing for Ballard Technology in Everett, Wash. For such an old technology it has proven quite robust, he adds.
Ballard has seen quite a bit of growth in 1553 during the last year, especially in unmanned aerial vehicle applications, Schuh says. MIL-STD 1553 is well-suited for basic command-and-control functions, he continues.
Most 1553 solutions are also commercial off-the-shelf (COTS) solutions, Schuh says. Part of the original buzz behind COTS was quicker time to market for products, which has become crucial in today's environment, he notes.
Schuh says there is tremendous pressure within the defense industry to get products deployed in four- to six-month time frames as opposed to 12. That is part of what makes 1553 so popular—it is a reliable standard that is typically available off the shelf.
One of Ballard's COTS product lines, Avionics BusBoxes are small, lightweight, embedded computers with built-in avionics databus interfaces making them a viable solution for data recording. These boxes offer as many as four to eight hours of databus recording while at 100 percent bus capacity. They have as many as four different databuses, serial, and discrete I/O functions all in one interface box.
Companies such as Excalibur Systems in Elmont, N.Y., and National Hybrid in Bohemia, N.Y., have also carved out a profitable niche in the COTS 1553 market. Excalibur officials announced that their EXC-1553PCMCIA/EPII device is moving to the company's legacy product line to allow the new EXC-1553PCMCIA/P1 card to take its place under the multifunction 1553 single-channel category for PCMCIA-type cards. The EXC-1553PCMCIA/P1 card is compatible with the EPII card and can be upgraded to an EXC-1553PCMCIA/P2 card allowing two 1553 multifunction channels on one PCMCIA card.
National Hybrid developed an affordable, portable 1553 to USB interface. Its 1553/USB Pocket Pal is a redundant 1553 BC/MT/RT Terminal with 64K words of internal RAM. It interfaces to a 2.0 compliant USB port, making a laptop/notebook an autonomous 1553 Work Station. The device's small form factor—it weighs less than 7 oz., and is tiny enough to fit within a shirt pocket—enables the user to take this 1553 USB nearly anywhere, company officials say.
The technology is solid but improvements and tweaks can always be made to "make the customer's job as easy as possible," says Ben Daniel, general manager for the GE Fanuc Intelligent Platforms avionics business unit in Santa Barbara, Calif.
For example GE Fanuc is releasing a new ROHS-compliant two-channel 1553 PCI Express card that will enable customers to interface with any PCMCIA card on all three avionics databuses—MIL-STD 1553, ARINC, and AFDX, he adds.
The move to an Express Card was essential as it is replacing PCMCIA on many portable PCs and customers are complaining how they cannot find PCMCIA cards, Daniel says. The GE product is for portable analysis, logger, and such solutions.
Some say tweaks are not enough. In order to handle modern sensors and digital video, a high-speed 1553 solution or other alternative must be developed or designers are faced with having to rewire legacy aircraft—which unless it is part of a scheduled retrofit can be an enormously expensive solution.
This expense is one of the main reasons why 1553 is still standing and may be for more generations to come. The average airframe is 27 years old, including aircraft such as the B-52 long-range strategic bomber and C-130 utility turboprop.
There has been a big push lately within the Air Force in getting hardware designers to comply with the FAA DO-254 standard, says DDC's Hegarty. FAA regulations have started requiring DO-254 compliance for new military air transport and helicopter applications.
DO-254 was developed by the avionics industry to establish hardware deployment guidelines for developers, verification engineers, quality managers, installers, and users. Hardware design, safety features, and in-service experience are just a few of the items involved in DO-254 certification, and subcontractors are struggling with how to certify their systems to DO-254.
"DO-254 is not a test requirement but rather a design methodology" that hardware OEMs must prove through extensive documentation to the prime contractor or integrator, Hegarty says.
Companies must come up with a validation plan not only for their hardware designs but any software component as well in order to comply with FAA requirement DO-178B for software validation, he continues.
DDC helps customers achieve DO-254 certification for designs using the Enhanced Mini-ACE and Mini-ACE Mark 3 family of 1553 products.
Acq Inducom, Oss, Netherlands, 412-615055, www.acq.nl
Actel, Mountain View, Calif., 650-318-4200, www.actel.com
Actis Computer SA, Geneva, Switzerland, (22) 706-1830, www.actic-computer.com
Aeroflex Colorado Springs, Colorado Springs, Colo., 719-594-8000, www.aeroflex.com
AIM GmbH, Freiburg, Germany, 761 452 290, www.aim-online.com
Alphi Technology Corp., Tempe Ariz., 480-838-2428, www.alphitech.com
Ballard Technology Corp., Everett, Wash., 425-339-0281, www.ballardtech.com
BCF Designs, Cirencester, England, (0) 1285 642434, www.bcfdesigns.co.uk
Beta Transfer Technology Corp., Bohemia, N.Y., 631-244-7393, www.bttc-beta.com
CMAC Microtechnology, Crewkerne, England, (0) 1460 270200, www.cmac.com
Curtiss-Wright Controls Embedded Computing, 703-779-7800, Leesburg, Va., www.cwcembedded.com
Data Bus Products Corp., Manhassett, N.Y., 516-365-8464, www.databusproducts.com
Data Device Corp., Bohemia, N.Y., 631-567-5600, www.ddc-web.com
Dynatem, Mission Viejo, Calif., 949-855-3235, www.dynatem.com
Edgewater Computer Systems, Ottawa, Ontario, 613-271-1101, www.edgewater.ca
Excalibur Systems, Elmont, N.Y., 800-645-1553, www.mil-1553.com.
GE Fanuc Intelligent Platforms, Albuquerque, N.M., 505-875-0600, www.gefanucembedded.com
Holt Integrated Circuits, Mission Viejo, Calif., 949-859-8800, www.holtic.com
Kontron, Kaufbeuren, Germany, 8341/803-0, www.kontron.com
National Hybrid, Bohemia, N.Y., 631-981-2400, www.nationalhybrid.com
North Hills Signal Processing, Syossett, N.Y., 516-682-7740, www.northhills-sp.com
Parvus, Salt Lake City, 801-483-1533, Utah, www.parvus.com
Sital Technology, Kfar-Saba, Israel, ?9-7633300, www.sitaltech.com
Tyco Electronics, Berwyn, Pa., 610-893-9800, www.tycoelectronics.com