Rugged Connectors Survive Harsh Environments
By Bob Hult, Bishop & Associates Inc.

For many years, connectors used in electronic equipment had it pretty easy. Computing and communications equipment typically lived in temperature-controlled, near clean room environments, protected from dust, moisture, shock, and vibration. Only trained, white-gloved technicians were allowed to handle interconnecting cables. But, that cozy relationship has slowly evolved, as devices became smaller, more powerful, and proliferated into new realms of equipment, handled by a wider range of users. Electronic devices have moved out of protected environments and into the outdoors, onto factory floors, under the hoods of vehicles, and into the hands of consumers.


Computers, for example, are now integrated into everything from large server farms to mobile devices that must survive environments that range from the battlefield to space. Communication equipment that at one time was installed in secure closets or switch rooms now may require installation at the top of a telephone pole, exposed to extreme weather conditions and salt spray. Industrial automation has moved high-speed network equipment down to the production floor, exposing it to corrosive gasses, continuous vibration, and dust. Medical equipment demands connectors that offer extremely high levels of reliability while being exposed to repeated sterilization cycles. Heavy earthmoving and agricultural equipment utilize automated engine and transmission control, as well as location-aware devices that are exposed to shock, vibration, extreme heat, mud, strong solvents, and rough handling by operators. Connectors that serve these applications have undergone transformation into a rugged breed of interconnects designed to survive these harsh environments.

The degree of ruggedness of a particular connector is often defined in terms of documentation provided by the supplier, including product specifications and test reports. It may also take the form of compliance to international standards such as UL/CSA, SAE, VDE, and IEC, as well as qualification specifications to military standards. The level of resistance to intrusion of moisture and dust, for instance is commonly documented by IP code for ingress protection. Many rugged connectors are rated IP65 to IP68.

The market for ruggedized connectors is being addressed by a large array of suppliers, which includes global connector industry leaders. But a growing number of smaller suppliers are also stepping in, and several of them are specializing in this niche market. Bishop & Associates estimates that of the total 2010 global connector market of over $45 billion, ruggedized connectors designed for harsh environments account for approximately $1 billion, or 2.4%, of the total market. If you add all military and aerospace connectors, which are typically considered rugged interfaces, that number grows to nearly $2.5 billion. Expanding demand for ruggedized connectors points to greater than average growth of this market segment over the next five years.

Getting your arms around this market can be a challenge, as the term ruggedized is a little vague, and is being used rather loosely within the industry.

Some connectors were designed specifically for harsh environments, such as aerospace, mining, nuclear, or heavy industrial applications. Every aspect of the connector, from contact design to coupling ring, is optimized for strength and interface protection, often sporting large, heavy, cast-metal shells, positive-locking mechanisms, and extensive moisture- and dust-sealing systems. These connectors perform in extremes of temperature, contaminated moisture, solvents, and mechanical abuse.









At the other end of the spectrum are several commercial standard interfaces, such as D-subminiatures, USB, and RJ45 Ethernet connectors that have been ruggedized with tough metal or plastic shells and waterproof seals to survive in nasty environments they were never originally intended for.

In some cases, connectors are being promoted as ruggedized with adaptations that may include extended temperature ranges, or modified contact designs that are more resistant to shock and vibration. Ruggedized connectors are now available in just about every configuration, including input/output, backplane, power, mezzanine, coaxial, and fiber optic.

Connectors designed to protect from electromagnetic interference (EMI) and electrostatic discharge (ESD) can also be considered ruggedized, as EMI-intensive environments are often a factor in many applications. Connectors in this category may feature shielding with positive low resistance grounding mechanisms, as well as low pass filters or transient voltage suppression devices integrated into the connector.

Hermetically sealed connectors form another class of connectors designed to support applications under exceptionally high heat and pressure conditions.

Based on the number of new ruggedized connectors entering the market, the connector industry apparently sees this market segment as having good growth potential.









Ruggedized connectors support a diverse collection of applications, including: 

• Military, vehicle-mounted equipment, Manpack, communications, surveillance, weapon targeting, bomb jamming and detection, including unmanned, air, land, and undersea vehicles.

• Avionic and space applications in which absolute reliability in exceptionally harsh environments is the top priority.

• Factory automation, including standardized industrial control connectors, as well as those designed for networking applications and robotics.

• Medical electronics, including monitoring, therapeutic, and imaging applications, and portable devices intended for consumer home use.

• Embedded computers deployed in applications that range from avionics to traffic lights.

• Government surveillance of public areas for homeland security purposes.

• Telecom and wireless communications, which requires equipment in remote locations exposed to extreme climate conditions.

• Geophysical exploration and down-hole production, demanding rugged interfaces that can withstand shock vibration, dust, extreme pressure, and temperature.

• Alternative energy production, including solar panels and wind farm equipment that are exposed 24/7 to extreme weather conditions and must perform for many years.

• Agricultural equipment has added many electronic functions, including GPS navigation, while operating in dusty, hot, conditions, with exposure to corrosive liquids.

• Transportation, including heavy trucking, off road earthmoving equipment, and rail transport.

• Outdoor signage, including large video displays.

• Mining equipment, including explosion-proof connectors that experience extremely rough handling.

• Security, including video monitoring and traffic management, which require long-term exposure to changing weather extremes.

• Food- and water-processing equipment requires frequent high-pressure cleaning cycles.

• HDTV broadcasting, which demands rapid deployment to sites of “breaking news.”

Many ruggedized connectors are offered as cataloged families, and are designed for use in a variety of equipment types that can range from cell phone base stations to recreational watercraft.

Other connector types may include features that make it particularly attractive for highly specific applications. The ability to survive multiple sterilizations in an autoclave, and features such as lightweight, ergonomic design makes a variety of circular plastic connectors from suppliers such as ODU, Fischer, and LEMO attractive in medical equipment applications.

Connectors that mate and disconnect within a sealed chamber of the connector are useful in areas of explosive gasses. 

Standardized M12 connectors have been designed for sensor/actuator applications in industrial automation and food/beverage industries.

Continuing pressure to reduce costs is impacting the military and industrial interface selection process. Standard military connectors such as Mil-C-5015 and Mil-C-38999 have been workhorse interfaces in military and heavy-duty commercial applications for many years. In an effort to reduce costs, armed services organizations have promoted the use of Commercial Off-The-Shelf (COTS) connectors. These commercial equivalents replace metal shells and strain reliefs with plastic configurations that are lighter, fully sealed, and considerably less expensive. Applications for heavy-duty interconnects in earthmoving equipment, trucking, rail transport, and agricultural equipment have adopted plastic connectors, some of which are fully intermatable with the military standard.


Connectors of all types that are capable of withstanding harsh environments represent a growing class of interfaces that is enabling the transformation of delicate electronic equipment into devices that “take a licking and keep on ticking.”

Bishop & Associates Inc. Comments: 

1. Many new ruggedized connectors are entering the market from a large array of connector manufacturers.

2. A ruggedized version of a standard connector, such as USB and D-subminiature, can move from a commodity to a specialized interface with a higher profit margin.

3. Applications in a great many market segments are stimulating demand for environmentally sealed connectors.

4. Potential component cost savings offered by the COTS initiative is driving demand for commercial versions of traditional military specified interfaces.

5. Standards play an important role in defining the performance of connectors designed for harsh environments.

Bishop & Associates will publish a detailed market research report on ruggedized connectors for harsh environments in Q411.

Robert Hult Director of Product Technology, Bishop & Associates Inc. Robert Hult has been in the connector industry for more than 39 years. Hult began his career as a sales engineer for Amphenol in Chicago. He joined AMP Inc. in 1972 and served in several management positions through 1996. In 1997, Hult joined Foxconn as group marketing manager for Intel in Chandler, Arizona, U.S. Prior to joining Bishop & Associates, Hult was the regional application engineering manager for Tyco. He can be reached at rhult@bishopinc.com.