By Max Peel
Many feel that product standards result from a group of people meeting in a resort area and creating a document that no one can use, then meeting at another resort and making changes to the document in a manner that no one can use. Actually, it is not quite that bad.
What composes a product standard? There are two main sections. The first details the dimensional characteristics of the connector. This area defines the footprint, mounting features, mating interface, position identification (ID) numbering scheme (rarely specified) and "envelope" dimensions. Rarely, however, is there a definition of the internal areas of the connectors involved, such as contact configurations. The dimensional characterization is supposed to guarantee intermountability, intermateability and interchangeability.
The second section details the qualification test plan. This section defines the functional characterization when exposed to a variety of mechanical and environmental stresses.
Intermountability implies that the footprint or equipment-mounting features are defined in a manner so that the user can assemble any manufacturer's connectors built to the standard to his system. Intermateability implies that the receptacle connector from manufacturer No. 1 can be mated to a plug connector from manufacturer No. 2, and vice versa.
Interchangeability implies that connectors from a number of manufacturers are both intermountable and interchangeable and can perform and function at the desired level. That is how it is suppose to work in theory. The reality is quite different.
Standards Organizations
Two standards organizations dominate connector standards — the Electronic Industry Alliance (EIA) for U.S. standards and the International Electrotechnical Commission (IEC) for international standards. It is not unusual for an EIA standard to take from two to four years to go through the development/approval cycle. An IEC standard may take as long as seven years, depending on politics. By the time the standard document is issued, the product is obsolete. In a sense, the document is an "after-the-fact" standard, with little or no guarantee of accomplishing its intended goal. This is particularly true today when time-to-market is nine to 12 months.
Electronic technologies have changed dramatically over the last few years with regard to technical approaches and time of implementation but the approach to connector standards has not. This has resulted in a variety of other organizations and special-interest groups getting involved in new connector/wiring schemes, including the Institute of Electrical and Electronics Engineers (IEEE) and the Personal Computer Memory Card International Association (PCMCIA). Certain user agencies (original equipment manufacturers [OEMs]) are creating their own standards as well. All of this results in increased confusion and further complicates information flow in determining connector design trends.
What Is Missing?
Many of the new product standards do not specify materials. Thus, the issue of material compatibility is left unresolved, particularly the plating systems and various base metals that can be used. Can these various intermated systems function properly when different materials are used? Obviously, some can but others cannot. The standards, however, do not address this issue, nor do they control it.
Also, there is no procedure or process in place to address the issue of proving total interchangeability. Although this is a difficult philosophical issue to resolve, the standards make no specific statements covering this issue.
This has proven to be a real problem. If manufacturer No. 1 is mated to manufacturer No. 2 and the product fails, they blame each other, with the OEM caught in the middle. In some instances, a manufacturer might state, "If you had used my mating connector, you would have no problems." This situation raises the question of who is accountable. Product standards do not address this topic.
Another issue is the lack of clarity relative to the position ID schemes. Some manufacturers use alpha, some alphanumeric or some numeric schemes, all which further complicates the situation. Standard definition is lacking in this area.
Other subtle areas also may not be defined. These include standoffs and plastic interlocking techniques that directly impact interchangeability. Thus, practical and useable product standardization for use to its fullest extent is nonexistent, certainly by the definition of desired interchangeability.
Product Standard Philosophy
What can be done? I recommend rethinking the philosophy of product standardization. Forget total interchangeability. In practice, it has not worked well. Think in terms of standardizing footprints and mounting features. Also, standardize on the envelope dimensions and the position-locating identifiers (so that all manufacturers use the same scheme). This approach simplifies the standard and allows a user to switch manufacturers without changing his hardware.
Both halves of the connector should be purchased from the same manufacturer. This resolves the issues of material compatibility, subtle feature differences, accountability and so on. The common criticism of this approach is that it will result in a single source (unless interchangeability can be demonstrated).
Multiple sources could be used if footprints, envelope dimensions and numbering schemes are the same. It could also result in allowing manufacturers to be innovative relative to the internal portions of the connector, which avoids potential subtle intermateability problems such as contact configuration differences and contact orientation differences. This is not well-defined anywhere in existing product standards. The "Golden Rule" in this approach is "intermateability is not recommended" and the concentration should focus on intermountability.
The Positive Side
So far, I've focused on the "dark side" of connector standardization efforts. There is a bright side as well.
Other standardization issues are discussed and worked on besides product documentation, particularly within the EIA. One of the more important areas is in the establishment, creation and maintenance of test procedures. Recent activities involve establishing procedures dealing with signal integrity — impedance, propagation delay, attenuation, crosstalk, etc.
Some excellent input has been given to the EIA committee (CE 2.0) dealing with this area. Humidity and thermal-shock procedures are being revised and a new thermal-cycling procedure is being created.
This group has also developed procedures for normal force and solvent resistance. It is now maintaining over 100 procedures for use in connector evaluation.
In addition, two basically new areas are being worked on. The first deals with current-carry capacity with a companion standard dealing with verification evaluation of power contacts/connectors. These standards will address many of the issues I've discussed in a previous article ("Power — The Lost Technology," January 2000, p. 14).
Of particular importance is the power verification schemes that have been put forth.
The second area deals with a new approach to product standards. This approach does not define a specific connector. It does define a test plan for evaluating and qualifying connectors to be used in a given application. This document is in the final approval stage with the title, "Environmental Test Methodology for Assessing the Performance of Electrical Connectors and Sockets Used in Business Office Applications." This standard focuses on performance expectations and criteria. It simply states that any connector used in this application environment must meet the functional criteria specified.
The unique approach contained in this standard defines thermal and durability preconditions that a connector may be exposed to prior to being used in its normal application. It also addresses thermal accelerator factors that will dictate the thermal durations to be used. Further, it has special sequences for specific plating options to evaluate susceptibility to time-dependent failure mechanisms (tin alloys, "thin" gold, gold flash palladium nickel).
This effort attempts to simulate real-world conditions for a variety of connectors that may be found in a specific environmental classification. Sample sizes for variable measurements have been significantly increased from those used in existing standards.
I strongly recommend anyone who is interested obtain this standard. It may not be perfect at this point but it is a large step forward and has the support of many of the top connector companies. Perhaps additional standards can be created using the philosophy and intent of the EIA to address other general or application-specific areas.
International Standards
My final comments deal with IEC standards. Its product standards have the same type of deficiencies as the U.S. standards, but its testing protocols are, by today's performance levels, very weak and do not address the issues of concern by user agencies. The test selections are antiquated and, in many instances, unrelated to real-world conditions. Its sequences are 30 years old and have not changed in that time.
On the other hand, the IEC has published a series of guidance documents on termination, which are excellent references and worth obtaining. If the quality of its product standards were equal to its guidance documents, I believe that wider acceptance would come. To do so though would require a total revamping of philosophy, and a diminishment of the involvement of protocol and more attention paid to technology.
I invite any reader to respond to my comments and ideas, whether angrily, constructively, benignly or emotionally. Let's debate the issue! We need to in order to be more responsive to the marketplace.
I do expect people will be kind, however, since I am now classified as a senior citizen, at least physically. Having said that, I will now retire to my office, think about other issues to be debated, give myself a raise and plan my trip for rest and recreation to the next standards meeting.
MAX PEEL, a Connector Specifier Advisory Board Member, is President, Contech Research Inc., 67 Mechanic St., Attleboro, MA 02703-2090; (508) 226-4800; Fax: (508) 226-6869.
