Top 12 Technology Trends: The Evolution of Proprietary to Open Source Connectors

By Robert Hult | April 27, 2021

Sometimes a custom connector design will remain a limited-use product. Other times, it may become a popular proprietary connector. In some instances, the evolution continues and the connector experiences widespread use as a commercial or open-source product.

This is the eighth installment in the Technology Trends series by Bob Hult, a collection of articles that review leading technology trends that have had a significant impact on the electronic connector industry over the past 20 years.

Proprietary connectors that are designed and manufactured by a single source are considered branded, and if adopted by many users, they can provide an excellent continuing stream of income. Fuzz Buttons from Custom Interconnects and the Cinch CIN::APSE connector from Bel Magnetic Solutions are examples of proprietary compressive interfaces designed to provide connection between two parallel conductive surfaces.

Fuzz Buttons from Custom Interconnects are used in applications that require high frequency RF signal capability coupled with excellent signal integrity and shock/vibration performance.


Each pathway on the Cinch CIN::APSE connector from Bel Magnetic Solutions relies on a spring-like contact that establishes a durable electrical connection using mechanical pressure.

Some of these proprietary interfaces were first associated with specific applications but later went on to become cash cows for their owners as they were more widely used. A connector may also be so unique and support a very specific application that it may remain a proprietary interface forever. Connectors designed for use in nuclear reactors or to provide a critical interconnect between stages of an intercontinental missile require exceptional design and material choices with production volumes insufficient to attract competitors. Even today, some proprietary connectors continue to exist in high-volume markets such as automotive, where manufacturers have chosen to tool unique connectors for specific applications, such as diagnostic, video camera, and radio interfaces.

The iconic color-coded plugs used to connect audio and stereo equipment have been in wide use since the 1940s.

Connectors are often created to fill emerging applications. The Radio Corporation of America Corporation introduced the RCA phono plug in the 1940s as a low-cost interface for its expanding line of record players. It soon was adopted in a wide variety of audio applications which continue today.

Some connectors evolve from their original application to became open source or de facto standard interfaces in entirely new high-volume markets. The 25-pin D-shell connector originally developed by ITT Cannon for military aviation systems (MIL-DTL-24308) was commercialized and became a common interface in many low-cost commercial and consumer computing and gaming applications. The Centronics Micro Ribbon interface developed by Amphenol for use in telecom applications became a standard I/O on printers.

The Qwik RJ45™ CAT6/CAT5E Modular Plug by Stewart Connector, a Bel group company eliminates the pre-trim step needed to assemble traditional RJ45 modular plugs. Applications for this connector include data, telecommunication, and industrial equipment connection.

The RJ45 modular plug was developed by Bell Labs for telephone applications in the 1970s and later became the ubiquitous Ethernet interface.

Other examples of globally standardized connectors include those certified by Deutsches Institute Fur Normung (DIN). DIN two-piece backplane and circular connectors have become commodity interfaces and today are tooled by dozens of mostly Asian manufacturers.

Fast-forward to the proliferation of mobile phones. Many suppliers designed their charging port with a unique connector which required the use of adapters to charge the many iterations.

Apple Inc. has a reputation for designing proprietary connectors to maintain control of attachments as well as pricing. The Apple Display Connector was a proprietary modification of the standardized DVI interface and appeared on selected Apple equipment before it was phased out in 2005. The Apple 20-pin and newer 8-pin Lightning connector continue this marketing strategy.

Apple’s Lightning connector is a proprietary interface unique to this company’s product line.

Equipment manufacturers hate to be limited to a sole source for a critical component. A manufacturer of a branded interface can manipulate pricing while posing a supply threat if the manufacturer cannot support demand or decides to withdraw from the market. In order to address that concern, connector manufacturers may choose to offer a license to a competitive second source. The Apple Lightning connector for example is available for licensing to other suppliers at a per-connecter fee. In some cases, only the physical dimensions of the interface are licensed, allowing the licensee the ability to offer a fully intermateable connector that may include enhancements such as footprint design, PCB attachment method, or type of termination.

In the last decade, we have seen a major increase in specifications that require all hardware be available for license at a fair, reasonable, and non-discriminatory fee (FRAND).

Large connector manufacturers have invested huge resources in the development of their flagship high-speed backplane connectors. Because the performance of the backplane is such a critical element of high-performance telecom and datacom equipment, use of a sole-sourced connector has become unacceptable. The solution for leading manufacturers, including Amphenol, Molex, Samtec, and TE Connectivity, has been to license a select competitor to assure their mutual customers of competitive prices and continuous supply. Performance at multi-gigabit speeds is highly influenced by slight variations of the signal path through the connector. Licenses for these leading-edge connectors provide extreme manufacturing detail to enable identical mechanical and electrical performance.

In addition to formal standards writing organizations, a collection of trade groups, multisource agreements, special interest groups, foundations, consortiums, and implementers forums have become active in creating specifications for and promotion of commodity connectors such as universal serial bus (USB), high-definition multimedia interface (HDMI), and Ethernet. Demand for simplification and reduced cost resulted in the introduction of the USB connector. The USB Implementors Forum, which manages this specification, has been aggressive in ensuring that the USB connector remains relevant by constantly upgrading its performance to meet escalating I/O demands.

The PCIe peripheral bus architecture has evolved into a leading data transfer protocol for computer-to-peripheral communications. This image shows Evercase Technology PCIe riser cards powered by a double-wired Molex Connector.


In some cases, a standards group will choose an existing connector, making specific configurations a standard, such as the PCI Express (PCIe), edge card connector defined by the PCI Special Interest Group (PCI-SIG), while the GenZ Consortium selected the TE Connectivity Sliver two-piece connector.

TE Connectivity’s Sliver family of interconnects extend the reach for high data signals inside networking equipment from the microprocessors to other locations while maintaining optimal signal integrity.

The open-source movement is the latest effort to reduce the cost and time to market of electronic equipment. These collaborative groups create specifications that utilize selected multi-sourced components as building blocks in standardized infrastructure designs that users can adopt without going through the costly new design and qualification process. The objective of open standards groups is to increase interoperability without the restrictions imposed by proprietary component or software suppliers.

Organizations such as the Open 19 and Open Compute Project are focused on the architecture of systems, including components, while other open standards organizations address software, power distribution, design automation, and test methodology. Organizations such as VITA have long promoted the concept of open and non-discriminatory licensing as a requirement for inclusion in a VITA platform specification.

The growth of open-source groups can represent an opportunity for connector manufacturers to expand the market for designated interfaces but can shut out alternatives until at least the next design cycle. Open-source hardware can also become a commodity product offering limited profit margin.

The evolution from proprietary to open-source components has required a change in mindset for connector manufacturers that often pride themselves in developing innovative, state-of-the-art solutions. The sharing of critical dimensional and material detail with a direct competitor would have been unheard of 20 years ago, but now it reflects the reality of doing business in today’s competitive market.

Like this article? Check out our other Bob’s Technology Trends Series, I/O connectors, and Standards, our Datacom/Telecom Market Pages, and our 2021 and 2020 Article Archives

Robert Hult
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