This following is a myth.

“JACK/PLUG – In electronics, a jack is a female part into which one inserts a plug, the male part.”

While often the case, the real definition is the jack is the more fixed of a connector pair and the plug is the less fixed connector of the same pair. Where two connectors are neither less or more fixed with respect to each other, both are a plug.

This was quite sensibly defined most recently in the IEEE-200-1975 standard. This standard was renewed in the 1980s and withdrawn in the 1990s. Even so it and IEEE-315-1975 form the basis on how to create reference designators in and around electrical equipment.

The notion Jack and Plug ever meant anything to do with a male or female contact, seems to have come about in the 1980s and 1990s. Somewhere in that time frame young engineers were not properly mentored by their elders in the way of good engineering practices. Bad habits leaked into the general population and now very few technical folks know how to properly annotate the references in harness designs and other electrical assemblies.

IEEE-200-1975 (also known as ANSI Y32.16-1975) serves as the last collection of knowledge dating all the way back to the 1950s in the MIL-STD-16 specification. UPDATE: See Below

Golden rules for harness reference designation from IEEE-200-1975 include:

  • The movable (less fixed) connector of a mating pair shall be designated P [where P means plug].
  • The stationary (more fixed) connector of a mating pair shall be designated J or X [where J means Jack].
  • If two cables are to be connected to each other, each of the mating cable connectors shall be designated P.

That last item is a mind blower for many. Yes this really means there is no such requirement to have J123 connect to P123. Efforts to try and achieve this are a notorious waste of time and such conventions are very easy to violate and, thus, break. A complete system on how to annotate an entire collection of electrical equipment is well defined in IEEE-200-1975. Despite it being withdrawn from active support in the IEEE, copies are still available from Tech Street and other standards suppliers.

Frequently heard statements:

Statement:
“The fixed/less fixed distinction doesn’t work when both are unfixed, as is commonly the case when cables are being extended or split.”

Response:
This was never a problem since Plugs can connect to Plugs.

Statement:
“Whatever IEEE may have wanted to establish, that’s not how it worked out…”

Response:
The IEEE did not establish anything. They documented what was once common knowledge, at least for technical folks, in the 1970s based on documentation dating back to at least the 1950s. It is clear the lack of mentoring is creating the break from tradition.

Statement:
“Plugs always have male contacts while Jacks always have female contacts.”

Response:
No they don’t. Look at any PC (an older one) with a DB25 parallel and DE9 serial ports – all Jacks. Look at the AC power “Jack” on your PC – male for a very good reason. Still other connectors, aerospace connectors come to mind, have both male and female pins in the same body.

Statement:
“Our engineers are from MIT so our custom annotation system is better.”

Response:
Perhaps, but the chance any super star engineer can outwit the collective knowledge of thousands of engineers and hundreds of thousands of man-hours documented in the standards… is laughable. Sure you may have the smartest team on planet Earth. Good for you. Keep their talents focused on the real engineering problems not engineering methods. Otherwise your A-Team will be in the unemployment lines after you miss your deadlines.

Statement:
“We mandate each Pxyz to match up to the same Jxyz.”

Response:
This instantly breaks if you have two identical sub-assemblies in your assembly since each item will have the exact same series of J numbers on its housing. IEEE-200-1975 provides a very simple and elegant solution for this scenario; Buy a copy and read it.

Statement:
“We ensure all the Jacks on all duplicate sub-assemblies are unique by writing new J numbers over top the ones printed by the manufacture.”

You just tripled the paperwork to track the “change” you made to an, otherwise simply identified, off the shelf item and must generate a whole new Control Drawing to track this change. Hopelessly ridiculous.

Statement:
“Do Engineers care about the proper use of reference designators?”

Response:
Engineers care. Engineeer wannabees don’t. Harsh, but true.

Other Standards?
I have searched the standards archives in depth to find any current standard that dictates a better approach than IEEE-200-1975. SAE AS50881 “Wiring Aerospace Vehicle” comes close, but really addresses how to identify the wires bundles themselves, not the connectors. UPDATE: See Below

The point is this. How to properly annotate electrical assemblies is nothing new. At some point the knowledge was dropped and chaos erupted causing, among other things, the bizarre concept of a plug meaning a male.

To Young Engineers:
If you are a young electrical engineer, you need to buy your own copies of IEEE-200-1975, IEEE-315-1975 and why not also IEEE-280-1985. Read them. Learn a great way to annotate. Amaze your boss by saying you will take responsibility for annotating your next project using a real standardized approach rather than home-brewing some half-baked method.

To Supervisors:
Supervisors, you need to find a way to pass on the knowledge stored in the above standards. If you don’t you are literally spending your project funding on the equivalent of learning how to read and write. Keep your engineers focused on the real problems to solve. Don’t spend time re-inventing the wheel.

To Contract and Specification Writers:
Make adherance to IEEE-200-1975 and IEEE-315-1975 a requirement. Save money.

If you do nothing else, please find a copy of IEEE-200-1975 and read it through once. It is very short.

Good luck.

UPDATE July 29, 2009

The commenter below discovered ASME, the mechanical engineering standards group, created a new standard to pick up where the withdrawn IEEE-200-1975 left off. It is called ASME Y14.44-2008. Apparently the void left by the removal of IEEE-200-1975 was felt by many so ASME came to the rescue with ASME Y14.44-2008. How embarrassing for the IEEE to have a mechanical engineering association pick up an electrical equipment standard.

I have ordered a copy from ASME and eagerly await its arrival for review and comparison. Stay tuned to this COSJWT post.

Well not really attracts lightning, but certainly allows for more pickup of lightning energy.

Last night on our Sunday Night Tech Net (Fauquier County, VA Repeater) a fellow named Bob brought up the topic of proper grounding for his upcoming coax fed 40 meter antenna. During the discussion about common ground points and other relating lightning protection possibilities, he recalled a story.

Seems , once upon a time, Bob installed some 120 Vac yard lighting around his property. The lighting worked quite well, but Bob immediately correlated a rise in damage to devices plugged into the ac power in his house with the installation of this yard lighting.

It would seem Bob inadvertently created a large antenna system which more efficiently coupled energy from lightning storms to his house wiring. Bob mentioned devices as simple as hair dryers were made useless by the surge energy.

The solution for Bob was to install good shunt protectors on his electrical distribution panel to quench the over voltage induced by lightning storms on his yard light wiring. Bob used MOV style protection.

The Polyphaser IS-PM240-xx is one option…

Polyphaser Surge Shunt Device for the house electical panel

For less protection and less money the Polyphaser PSP-240 may help…

Small Polyphaser Surge Protector

This year Virginia has been hit with many thunderstorms so lightning protection is a popular topic for ham radio folks as well as folks who are simply trying to beautify their yard with lighting. If you are considering extending the wiring in your home you are well advised to add protection like Bob did to protect your loved ones from the much larger antenna you have made. You might also consider low voltage lights and/or an isolation transformer between your house and outside lights. There may even be a NEC requirement for this, but I am not sure.

When in doubt, seek out the advice from a competent licensed electrician.

There is also a rumor warranties on big ticket items like washing machines, dryers, heat pumps, etc. do not cover damage caused by surges since you are “expected” to provide this protection for your house. When you look at things this way, the few hundred dollars spent on a good panel mounted surge protector is a real steal.

For those of you building Elecraft Kits like the K2, KX1, etc. you should consider using these lead bending tools to form your components perfectly.

Speedy Bend Lead Formers

It took a little while to locate a source, but I finally found and purchased a set from Production Devices in California.  They are called “Speedy Bend.”

sparkmovie.jpg

For you beginners wondering about what static electricity is or for you folks who already do know, take a ride in the way back machine and watch this old government video. While a little long in the tooth it does a terrific job explaining and demonstrating various examples of static electricity.

The Amazing Power of Static Electricity

This video was made back when the English language was spoken good… ah I mean well.

This is well worth the twenty minute length.

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