Connectors: A History of Their Technology?

dpbsmith asks: "It seems like a simple engineering problem--construct a device for easily and safely connecting several dozen wires at the same time--but the variety and creativity in their design over the years has been amazing, and, clearly there have been trends, fashions, and styles. In the fifties and sixties, virtually all connectors were roughly similar to the D-Sub design used for RS-232. A stiff, straight pin engaged a springy socket that contacted and bore against it on all sides. There were minor variations in shape and placement; the Amphenol Blue Ribbons (think Centronics), the connectors into which circuit boards engaged, but they were all variations on a theme. I was absolutely astounded the first time I saw a modular RJ-11 connector. Cheap, effective, and utterly unlike anything I'd ever seen before. Who invented these? Western Electric? Recently, we have the USB connector and the Firewire connector, obviously members of the same family (and a cheap-and-cheesy-seeming family it seems); on the other hand, my telephone and my digital camera have connectors that are very small and snap in with a positive lock that must be released with a squeeze, obviously yet another fundamentally different design. What do people know about the design, history, and engineering behind connectors over the years? Is it all hidden away, trade secrets of the connector companies, or is their a story that can be told?"

Comments

The eternal question...

[DanCracker]

If we're talking about connecters, we should take time to ponder the mystery of BNC connecters, their origins, and what the hell BNC stands for anyways!

Re:The eternal question...

[simpl3x]

my grandfather made automated machinery to produce these connectors. interestingly, though amphenol and others made these connectors, they never really automated the process--i guess with military contracts, the govenrment will pay whatever is necessary--so, machinists created each component for a connector individually. expensive!!! my grandfather automated the process, creating a machine which would create one a second, which was difficult at the time--ww2. the machines ran without much attention, using statistical methods and optical comparitors, they made sure the quality was high. and, he was paid more for the scrap copper than for the material required! so this business ran rather well! amphenol later purchased the business. it is also interesting to hear the advantages which one could get by producing electrical components during ww2--atomic clearance! you could pretty much get whatever you wanted. equipment was scarce at the time, and with clearance you could pull up to the warehouse and take whatever you needed from those without clearance. being caught reselling machinery and such was nearly treason.

game reference

[iocat]

One of the coolest things about connectors is that the Atari 2600, C64 and Sega Genesis all had the same 9-pin connector. You can hook a Genesis pad up to your 2600 and it works well (B is the only button that works, along with the D-pad). There's even a hack for making the Genesis pad work with the two-button 7800 -- sadly I can't find the link atm. Coolest thing I've seen recently is a converter that lets you use PlayStation dual-analog controllers on the Atari 5200. I believe I saw something about it here.

Connector technology

[base3]

A more egregious example of the connector conspiracy: Dell's innovative arrangement of the pins on the standard ATX power supply connector (e.g. the swapping of +12V with ground). The result is that upgrading or replacing the power supply with a non ($$$) Dell model will result in a short, and possibly a fire.

Perhaps they should rename themselves "Packard Dell."

Favorite connector

[rongage]

Personally, my favorite connector has to be the Camlok E-series power connector. There is just something "interesting" about a connector that is rated for 400+ amps of current flow. And just TRY to break one or pull it off the wire...

For multipin, I would have to say that the old IBM Latchback connectors are tops on my list. 240+ pins, all designed to mate at the same time, all gold plated, and designed for low level signals (unamplified audio for example). Single cam based latching mechanism, keyed, and easily maintainable.

Of course, if you have never work in a concert hall, you probably will NEVER see any of these connectors in real life....

Connectors in my PC

[Waffle Iron]

Hmm... I'll waste some time here and assign grades to the connectors in my PC on a scale of 1 to 10:

• Keyboard/mouse DIN - 5. Works OK, but hard to orient. Making mouse and keyboard identical was stupid. Feel not very satisfying.
• AC Power cord to power supply - 9. Very satisfying feel. Easy to use.
• AC Power cord to wall outlet - 6. A true classic. Rated down because of childhood memories of annoying transition to 3-prong grounded outlets. Could have used better protection against fingers/children.
• 1/8-inch audo jacks - 8. Easy to use. It would be better if all audio equipment would use the same connector (i.e., no 1/4-inch or RCA jacks).
• USB connector - 9. Sure beats previous solutions. Would be nice if the up/down orientation distinction was more obvious.
• RJ-11/RJ-45 modem/network - 8. Very convenient; elegant design. Achilles heel: if you try to pull the cable out of a tangle of wires, you're likely to break the little retaining tab and ruin the cable.
• 15-pin VGA video - 5. Hard to orient, screws are inconvenient (but easier than the 3-BNC connector alternative). Technical achievement award to those who figured out how to kludge 1600x1200 signal frequencies through this thing.
• 9-pin serial connector - 3. Boring. Same problems as VGA. Should have been done with 2 or 3 pins. (Old larger serial connectors rate a 1 for total overkill.)
• Parallel printer connector - 1. Choosing to save money by not putting a shift register in the printer was one of the most unfortunate decisions in the history of personal computing. How many kilotons of copper have been needlessly wasted on all those wires? Cable is thick, heavy and expensive. This is a classic example of how the marketplace can converge on a suboptimal solution and then get locked in.
• Centronix printer connector - 1. See previous entry. This end is especially bulky and cheap feeling, to boot.
• Internal IDE connection - 3. Ribbon cable is hard to manage. Master/slave business is a hassle. Doesn't seem to be a clear standard on orientation keying. Hard to tell when properly seated. Max length too short.
• Internal SCSI connection - 3. Same problems as IDE (except for length limitation), plus additional confusion over terminations, ID numbers, and incompatible speeds and widths.
• CD-ROM audio - 6. Not too bad, once you track down where the connection is on the motherboard.
• Hard drive power. - 9. Surprisingly easy to use, given the amperage it must support. The twisting behavior is really nice. I've never had problems with these.
• Motherboard power - 7. Doesn't stand out much, no big problems.
• Misc motherboard stake pin connections - 2. No physical alignment constraints and poor silkscreen markings make these a big hassle.
• ISA Slots - 3. The lack of a proper mechanical specification for these caused a lot of alignment headaches. It's a good thing you could use the slot screw to get the thing all the way in with brute force. Things got better once most cards shrunk to the size of a business card; less to go wrong.
• PCI Slots - 6. Relatively unexciting.
• PCMCIA Slots - 8. I'm amazed at how all of those tiny pins connect without getting crushed. Good feel, ejection button is fun.

Re:Connectors in my PC

[Hodr]

I can count by the number of scars on my fingers how many times I have attempted to unplug the power cable for a hard drive.

These have got to be the worst designed plugs in the universe. They go in easy, and are impossible to remove.

Why can't we invent a safer electrical plug?

[Anonym0us Cow Herd]

In north america, it seems that all computer power cords are standardized. I don't mean the standard electrical plug. But the "other" end of the cord. Whether it plugs into a calculator, adding machine, comptuer, monitor, or some other types of equipment.

It has a standard sized six sided shape with three holes for metal prongs to fit into.

Perhaps, you've seen a cord with a connector that is the opposite gender of these. It might, for example, but a cord comming out of a monitor with a connector that accepts a standard computer power cord.

This cord has metal prongs (male?) but a sheath around the prongs into which the bulk of the plug from the other end fits (femals?).

If you know the kind of connector I'm talking about, then why can't electrical power plugs work like this?

At present, electrical plugs have metal prongs that can be touched with your fingers while the plug is partially inserted into the electrical outlet. What if there were a plastic "fence" around the group of prongs so that it was impossible to touch the prongs while it is being inserted into an outlet? The outlet would have to have the "cutout" for this plastic fence to fit into.

Anyone who has plugged an Apple monitor's electrical cord into the Mac so that the Mac controls the flow of power to the monitor knows what I'm talking about here. It is impossible to touch the prongs while you're inserting the plug into the socket.

RP-TNC connectors

[sparkmanC]

With the recent 802.11b Wifi craze I'm surprised anyone hasn't mentioned the RP-TNC connectors that appear at the back of the popular Linksys WAP11.

They have proved very hard to find, and expensive to order. The connector or adapter cable often prove to be the most expensive part of a homebrew antenna!

Does anyone have any antenna / RF cable tips or know of stores in the SF bay area?

Andersen Powerpoles

[Jonny 290]

I love connectors. I love sticking wires into a DB25 to make my TI82 talk to my PC. I love crimping RJ45's (nothing beats that satisfying perfect crimp). I love squishing down a 50 pin IDC with a pair of visegrips (or a vise, if I'm lucky :)). Maybe it sounds trivial, but there's just something about connectors and interfaces that makes me smile. Yes, I am insane.

Might as well plug my favorite DC power connectors, Andersen Powerpoles Modular, color-coded, genderless, super-easy to assemble, safe, positive click on connect, etc. Emergency services are quickly adopting them as the standard for all 13.8v (12v nominal) gear for their setups. Perhaps a few cents more than the cheap barrel connectors or Molexes, but they're definitely worth it. I've driven over 12-year-old Powerpole connectors and they're none the worse for wear.

(no connection between me and andersen besides happy customer status, btw.)

Ultrasound Connectors

[Arandir]

Medical Ultrasound systems have a unique connector problem. An ultrasound probe has to connect to the ultrasound machine, but there are a huge number of signals that must get transmitted. The traditional ultrasound probe has a connector that looks like a huge 2" by 5" RS-232 plug with up to 256 pins (more in some cases).

To prevent constant pin breakage and bending, most ultrasound machines have special guides on the ports (jacks) so that the plug can only be inserted at a precise angle. But it still happens. When you've paid up to $50,000 for an infant cardiac transesophogeal multiplanar probe and you break a half-cent pin, you tend utter words that should not be uttered near an infant needing such a diagnostic examination.

Acuson invented a new type of connector for their Sequoia line of ultrasound systems. The "MP" connector is a flat plate that rests snuggly against another flat plate in the port, held secure by a quick release knob. Imagine a very large inkjet cartridge connector. Unlike an inkjet connector, they're very rugged, and spec'ed out a heck of lot tighter. No more broken pins! And they're a lot easier to attach and detach than the old style.

not 2N+1

[Anonymous Coward]

If you have a hermaphroditic connector with N pins, how can it be orientation agnostic? There is just one way you can connect.

But there are two ways you can turn a connector 180 degrees for it to mate with one identical to itself: around the axis defined by the pin tips or along an axis perpendicular to that and to the cable itself. In the first case you only need N wires (see the Anderson cable mentioned in nearby posts) but in the second case you need 2N+1 unless you want cross-over.

I tried to explain this to Jef over email, but even with drawings it didn't work out very well. I am sure that if I could explain in person with hand gestures he would have got it.