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...

[BiOFH]

Sorry -- According to the one source no one seemed to bother with (Amphenol themselves) it is, as the coward pointed out, 'Bayonet Neill Concelman' and was named for Carl Concelman (and not Carl & Concelman).

This was an easy find:
http://www.amphenolrf.com/products/bnc.asp

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 genders

[lingqi]

I was six when i first heard of the term "male" and "female" connectors. Even though I keep pestering my dad about
1) which one is male / female, and
2) why they name it something stupid like that

he just kept "umm... ahhh"-ing and never answered.

I was like 17 when it finally dawned on me why they named it that way. ha! then it all made sense.

moral of the story are:
a) who says electrical engineers / connector designers are not perverted?
b) to save yourself trouble, don't talk about male/femail connectors in front of little kids.

Re:connector genders

[K8Fan]

The real mystery is why a female panel connector is called a "jack".

I remember being embarrassed the first time I had to explain the difference between "male" and "female" connectors when I was in high school.

Re:connector genders

[K8Fan]

When I was doing some part-time work crewing for a "sound reinforcment" firm, I could never remember which way round the XLR connectors went.

I did sound on a touring edition of a broadway show back in the early 1980s. The system supplier was Masque Sound, who did most of the shows on Broadway. The bad habits of the stagehands forced the companies to do things a bit differently -

Every single XLR cable was female - on both ends. Every XLR panel connector was male.

The reason was that the stagehands insisted on pulling cables out by the cord. Apparently, pressing the little tab was too much work. Masque found that the female XLR would be the one to break, so they used females only on cables, because they were easier to repair. They would go through and replace every female XLR on every a 32 channel mixing board.

Even more bizzarely, they used 2 prong polarized AC cords for speaker connectors. The speaker cabinets had duplex outlets on the back.

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."

Power supply adapters and plugs...

[pubjames]

Talking about connectors, one thing that really mades me mad is the amount of power supply adapters we have to have these days. My office floor is littered with them, for net routers, printer, laptops, displays, mobiles etc. etc. Why can't we have two circuits? And for that matter, why are electric plugs so big. In the UK the are enormous. Many things these days only take a tiny bit of power - can't we have smaller electrical plugs? On my travels it seems that in the rest of the world electrical plugs are pretty big too. Is there anywhere with little dainty ones and without huge power adapters? Japan perhaps?

Re:Power supply adapters and plugs...

[K8Fan]

The UK AC plugs may be large, but they are safe, which is a lot more than I can say for the horrible US AC plug design. I visited the UK last year with a bunch of US multi-voltage video equipment. My British hosts were stunned at how bad the US plug design was, and how easy it would be to shock yourself as you inserted or removed one. The hot blade is exposed with AC power on it - if your finger should slip, you get zapped.

The UK plug design is plastic along the length of the blade, and only the end is metal. By the time you see the metal tip of the blades, the circuit is already broken.

Ok, so let me get this straight

[Raul654]

It might be easier if we switched from 60Hz to something around 20kHz.

You want to overclock the power lines?

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

[Jonny 290]

And I'll take the RF and audio side. :)

1/8" stereo audio - Cute, impossible to insert incorrectly, noisy (electrically), easily broken.

1/4" audio - Big and ugly, until you get used to it. Then you get 18 hours on a modular synth and learn to love them.

RCA - What, like 100 years old or something? Classic, and easy to use.

XLR - Good idea, bulky, but positive contact, locking, and keyed. Pro shops use this for a reason.

UHF (PL-259 / SO-239) - Ancient, gives an impedance spike on the line, fucking impossible to solder with anything less than a 150 watt iron.

BNC - Beautiful. Love this one. I'm converting all RF gear in my shop to BNC, bit by bit. Power handling isn't quite up there, but you can go N for that.

N - Tough, reliable, smooth (impedance-wise), and dead simple to install once you get the hang of it.

F - KILL THIS FUCKING CONNECTOR. Yes, I know it costs you $0.03 per unit, but it's annoying and the inherent 'center conductor IS the pin' is remarkably irresponsible. I'd feel so much better if that cable TV jack on the wall was a BNC.

Re:Connectors in my PC

[Yarn]

* Keyboard/mouse DIN - 5. Works OK, but hard to orient. Making mouse and keyboard identical was stupid. Feel not very satisfying.
Evolution at work, the tranition from DIN to minidin occured at the same time as the transition away from serial mice.

* AC Power cord to power supply - 9. Very satisfying feel. Easy to use.

Ah, yes, the trusty IEC connector. AKA kettleleads in the UK. Great things, pity the distribution boards are so expensive.

* 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.

I'd not give US wall plugs more than a 3. At least they have flat connectors, unlike those crappy EU ones. Unsheathed, tinny wobbly little things. UK three-pin plugs are far better.
* 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).
Not robust enough, I've wrecked a couple of these.

* USB connector - 9. Sure beats previous solutions. Would be nice if the up/down orientation distinction was more obvious.

OK. I guess.

* 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.

Agreed

* 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.

Should see old SUN equipment, the connector contains little coax connectors.

* 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.)

Most of the extra pins have a use. Flow control for a start. Important when you're going to throughput with as little silicon as possible.

* 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.

Greater throughput than other tech at the time. Similar connections were used for scsi.

* Centronix printer connector - 1. See previous entry. This end is especially bulky and cheap feeling, to boot.

The good thing about these is that they're rated for about 50V. If you have a lot of relays to control these things are ideal, and commonplace.

* 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.

Designed to a price.

* Internal SCSI connection - 3. Same problems as IDE (except for length limitation), plus additional confusion over terminations, ID numbers, and incompatible speeds and widths.

More modern internal SCSI should have D-shaped connectors, nicer.

* CD-ROM audio - 6. Not too bad, once you track down where the connection is on the motherboard.

The latch is a mixed blessing, good in that you don't knock it out, bad in that it's really hard to release when it's clustered up with the rest of the junk on a mobo.

* 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.

MOLEX. I've had these fall apart on cheap PSUs.

* Motherboard power - 7. Doesn't stand out much, no big problems.

No problems, as long as you're using standard equipment. Some large manufacturers pull tricks like swapping positions of different power levels. A multimeter helps.

* Misc motherboard stake pin connections - 2. No physical alignment constraints and poor silkscreen markings make these a big hassle.

Cheapness rules here

* 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.

Yet another near-dead connector. Lasted well considering. I've had more problems seating PCI cards with their smaller connectors.

* PCI Slots - 6. Relatively unexciting.

Ayup. You missed AGP. I'm amazed how densely that bastard is packed ;).

* PCMCIA Slots - 8. I'm amazed at how all of those tiny pins connect without getting crushed. Good feel, ejection button is fun.

Not much finer than an IDE connector, and a better alignment system.

Missing:
slot1 (pretty good, but obviously a dead end) 7,
Socket7, 8, A, 370 etc etc. some great fun with no alignement, socket 8 worthy mention for being two different pin densities in the same connector. 3-9
Firewire: good design, 10
Floppy power: what internal power supply should be :)
BNC.. great for signals
Triax, for studio and location video feed: FAR TOO PICKY 2
FC and other fibre connectors, incredible, they do near instantly what takes me by hand about 5min.

Re:Connectors in my PC

[Tablizer]

Your forgot one:

• Human sex organs - 7. Nice, but it would be better if the male had it's own female connector slot and double-jointed-ness in the pin for the the times that male can't find an opposing connector.

Re:Connectors in my PC

[tzanger]

Making mouse and keyboard identical was stupid.

No, what was stupid was not just running all wires to both connectors. The only difference between the two is that the keyboard clock and data are run to two pins on the keyboard (and not connected on the mouse) connector, and the same thing for the mouse. Just run all the traces to both and you can plug either in to either port.

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.

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.)

another design center, another solution

[wfmcwalter]

It's interesting to see how the same old problem is solved in a new way when your target user varies from the usual.

I'm always impressed by the connectors for peripherals (generally controllers) on modern video-game consoles. Consider, if you will, the humble playstation connector:

• It can be operated successfully by a two year old, with no training or supervision.
• It's impossible to connect it wrongly.
• It appears to be entirely immune to the harmful environmental contaminants associated with its users (small children and lonely geeks).
• ... and it absolutely, positively will not break.

If only connectors for "grownups" were designed this way.

Re:Connectors in my PC - usb

[victim]

The USB mechanical spec calls out that the USB logo be molded on one side of the cable in such a way that you can feel it and the other side be smooth. The logo is specified to go up.

And all was good.

Until manufacturers could save $0.02 by putting their jacks on upside down or sideways. Now you have a bunch of nicely polarized cables that you can orient blindly in the mess of cables, but have no idea which way the jack is oriented. :-(

(Yes, I have an upside down computer from a vendor that knows better and screwed me for $0.02.)

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.

Ultimate minimalist connectors.

[victim]

The crufty among us will remember the ultimate minimalist connector. The original ethernet (thick wire) used a large coax cable as the backbone. You connected to it by drilling a tiny hole and inserting your tap into the cable in such a way that it made contact to the core and shield without shorting anything and wiping out the whole network.

It really made 50ohm BNC look good when it came out. :-)

Re:RP-TNC connectors

[DMDx86]

Open it up, and solder in some normal connectors...

The reason why 802.11b equip. has these funny connectors is becuase the FCC mandates that wireless equipment have "difficult to obtain" connectors.

If you don't want to solder, then go to http://www.fab-corp.com/ and see if they have what you want.

Basic connector type information

[lanner]

So, here is what I know. Not everyone here knows their cables or connectors nor do they need to. Here are some simple things to help you out with.

RJ stands for Regents Jack. RJ11 is your typical 2-6 pair telephone jack. RJ45 is your typical 4-5 pair Ethernet pin jack, also gets used for DS1s.

BNC is a Barrel Node Connector. BNC gets used on test equipment, older coax cable NICs for thin or thicknet. Also DS3 twinax cable interfaces. That screw in on the back of your TV set? F-type.

Tons of pretty pictures;
http://www.cmsa.wmin.ac.uk/~alan/compon ents/conn/

Molex appears to have a nice connector tutorial for you to check out. I need to look this over myself;
http://www.molex.com/training/bce/gstoc.h tml

Get yourself a Molex catalog. Every type of cable connector you can imagine. Go to their products page and browse around.
http://www.molex.com

Do not forget Amp, even though their web presence sucks (or last time I looked)
http://www.ampnetconnect.com/

Random cable interfaces, with some pictures;
http://www.peakaudio.com/CobraNet/Netwo rk_cabling. htm

Cable Types for 3Com Products
http://support.3com.com/infodeli/tools/m isc/cables /cabling.htm

Unix Serial Port Resources: Sun Serial Port & Cables Pinouts
http://www.stokely.com/unix.serial.port.r esources/ A-B-Ycablepinout.html

IEC has standards, like that power plug on the back of your computer -- an IEC 320 plug.
http://www.iec.org/

Your typical U.S. three prong power plug is an NEMA-5-15P (P for plug), and the receptical is a NEMA-5-15R. Here are some charts with pretty pictures;
http://www.leviton.com/sections/techsup p/nema.htm
http://www.quail.com/locator/nema.htm

SCSI connectors, pinouts, and protocols, and some IDE/ATA stuff too;
http://t10.org/

Do not forget about the Fiber Channel and HIPPI;
http://www.t11.org

PCI card interfaces;
http://www.pcisig.com/

EIA/TIA;
http://www.tiaonline.org/

Whoa, I just found this... standards for wiretapping?;
http://www.tiaonline.org/standards/ carnivore/

Cisco, always a great place to look and learn. Common LAN interfaces from what I see;
http://www.cisco.com/univercd/cc/td/doc/prod uct/la n/cat6000/6000hw/inst_aug/0bcabcon.htm

More Cisco, including V.35 and X.21 pictures;
http://www.cisco.com/univercd/cc/td/doc /product/ac cess/acs_mod/cis3600/hw_inst/cabling/marcabl.htm

Arg, I had to repost this because Slashdot says, "Your comment has too few characters per line (currently 26.9)." That sucked and needs to change.

If you have more references, please let the world know. I know stuff, you know stuff. Put your stuff here.

Re:Basic connector type information

[RedSynapse]

You are incorrect on at least two of your definitions.

RJ stands for Registered Jack (check out the glossary at the end of this FCC document).

BNC stands for Bayonet Neill Concelman

Don't have the right connector?

[msheppard]

Cut both cables with scissors.
Strip the wires about an inch (with your teeth of course).
Twist the right ones together.

Electrical tape and solder optional.

M@

Re:(yes) Re:British Naval Connector?

[HughsOnFirst]

I had no idea that there was any need to connect anything to British Navels. I had an English girlfriend 20 years ago and don't remember anything about any _electrical_ connections anywhere. Seemed like a pretty standard bellybutton to me. It this part of some new broadband in the womb initiative?