The Basics of Connectors

I liked very much this small course ad it focuses very well almost the entire connectors range in a simple and very understandable way. I was already aware of what are all the types of connectors shown and described but to find them all in a single place, explained and correctly named includes for me a number of advantages:

• One of the most difficulties to find a connector for buying is to name it correctly instead of making a too generic research in the online shop (e.g. Farnell, but also the other big distributors as well). You can spend hours to find the right way to describe a connector and "catch" the exact key feature to find them on top of the search page.
• Some things was not totally known and one extremely useful part is the main (and correct) usage. It is true that some connectors costs so much that in the prototyping phase some compromises will be accepted but it is also true that I see in some of my past projects and also in other board projects that assume to be professional the usage of a totally wrong connector
• Nice to have a all-in-one guide.

The most difficult part IMHO in this kind of "courses" is just the creation of the final questions. I wrote a number of books on technical arguments with this educational structure and the biggest difficult I met was just the creation of the final questions. The point is that every question should be almost complex to require the explained knowledge but in the meantime impossible to equivocate.

Supposing that the user read and learn the document then try to answer honestly to the questions, the point

Sounds confusing: there is not only just a single correct answer (IDC) that can be understood. Maybe that this is the better, but if someone has a minimal experience in cable creation in his life why not answer crimping ? Typical is the assembly of network cables, that does NOT require pre-stripping of wire insulation, as well as the flat cables that are assembled with another crimping machine just pressing the top of the connector to the button with the cables in the middle. To be more confuse also thinking to the connectors like - to refer to a real world well-known example - the flat cable to connect the PI Camera to the Rapspebrry PI or the touch display these are connectors that hosts a special flat cable that does not require any kind of stripping.

As my consideration above may depend most by my ignorance instead of a seeing the things in the right perspective it will be great is someone confirm or contradict me about this.

Enrico

IDC doesn't involve crimping but pressing and the IDC contacts do not (overly) deform. That's why the tools are often called connector presses.

Crimping is the deformation of the contact lug (usually the terminal) to form a mechanical restraint and contact with the wire.

There are some connectors that use IDC and crimping. The IDC portion remains non-deformed but the crimp section is deformed for mechanical strength.

This video uses the term Press.

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The video implies that you have to have French polished nails.

Here's another (for non French manicured and polished nails).

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Both videos imply that the wearing of a metal bracelet or wrist watch is mandatory.

FPC cables have often have exposed ends and don't need any insulation to be displaced. They are placed into their mating connector whether they are ZIF or friction fit.

There are also crimped IDC connectors for FPC cables (usually of larger pitches).

Thank you, it is a very good clarification. Remain the fact (maybe my prejudice?) that - one example for a lot of cases - the network cables never require other than the right wires positioning inside the connector then the only option you have is crimping them. it is rare and probably the exception, a case where you should solder something to make a network cable, if you exclude the coax one that I remember on the historical NE2000 Novell network boards. But this was another age

Enrico

Hi Enrico,

It's good to know that I can be still helpful.

Just remember that UTP network cables are use Modular connectors and the way they are wired up may conform to the a suitable RJ (registered jack) standard.

So there's not such thing as an RJ45 connector it is a 8P8C (8 position, 8 connection) modular connected up to the RJ45 standard.

Those not aware of the proper wiring will likely experience connection instability.

Electrically the connections may be right but from the Characteristic Impedance and crosstalk rejection may be unacceptable.

Hi Enrico,

It's good to know that I can be still helpful.

Just remember that UTP network cables are use Modular connectors and the way they are wired up may conform to the a suitable RJ (registered jack) standard.

So there's not such thing as an RJ45 connector it is a 8P8C (8 position, 8 connection) modular connected up to the RJ45 standard.

Those not aware of the proper wiring will likely experience connection instability.

Electrically the connections may be right but from the Characteristic Impedance and crosstalk rejection may be unacceptable.

Hello

Thank you again. My questions is: by the exclusively point of view of

does NOT require the pre-stripping of wire insulation

Are not these equivalent? It is the point I can't focus. Why we should not consider an RJ45 as well as a flat cable connector (not the models for soldering) all not requiring pre-stripping? This is what occurs. If not, what we should strip before assembling the connector?

Hi Enrico!

Ah, I see your point, basically the language varies a bit, for example people say 'crimping an RJ45 connector' which also means using a tool to assemble the modular plug which uses IDC.

The outer jacket (cream/white color in the photo below) is cut/stripped back, but the wire insulation is not stripped.

The manufacturers themselves refer to the tool as having a crimp action anyway. There is some metal deformation for IDC connectors, so it isn't so bad to call it a crimping operation.

Generally if someone says they are 'crimping up a network cable' it is usually understandable from context.

They are amongst my favourite connectors, because they are compact, and the pre-assembled cablespre-assembled cables are so cheap, they can be used for many non-networking scenarios like RS232 or UART connections or anything you like pretty much (can also carry a decent amount of power) and naturally polarized etc., and the pre-assembled cables are already pre-twisted so useful for carrying balanced signals too. Plus every office has them, so you're never short of a cable.

Although I have an assembly tool, it isn't essential, invariably I'll use the pre-assembled cables where possible simply because they are low-cost. Usually long runs terminate in a socket connection anyway (e.g. patch panel) so the short connections do not need the tool when pre-assembled cables are available at low cost for the short patches. For custom cables I chop them in half and stick on whatever desired connector:

Although there are self-assembly push-fit 'kits' like this too (the black shell has the socket on the right side, so any network cable can be plugged into it without needing to chop it):

But for personal use the 9-pin D receptacle connectors9-pin D receptacle connectors are low-cost, so I generally just solder them up myself.

Hey Shabaz! The small finesse finally has been caught ! : D

Nice explanation, a sort of great and useful appendix to the course. It is the worth that pchan consider this option.

BTW in this world of connectors I am thinking to the IBM 360 / AS 400 and so big coax cables, the channel networking if I am not wrong. There was a curious method, the connectors was able to be injected i a cable to make a "Y" duplication or "T" or just to connect more together. I have always saw this method with a certain respect for its originality. Maybe something proprietary of IBM. Archaeology ...

Thanks! Enrico

Hi Enrico,

Thanks!

That's interesting, I did hear there were connections that could be literally tapped directly into big coax cable at any point along the length of it. When I first started to work the first year I saw the thinner coax and BNC connectors and T-adapters etc, using the CSMA procedures. It disappeared and was replaced with the RJ45 with UTP cable quickly so I didn't get to see it long enough, but I do remember frequently banging head underneath table trying to connect up computers to the BNC socket : )

That would be a 10Base5 vampire tap. For 'hot' installs or more commonly for those not trusted to terminate coax properly with the alternative type N connectors

Shabaz, Dave is only correct that it is 10Base5 vampire tap. But sorry the rest is just not true. Back in the day We used to lay a backbone cable, and then add nodes. which contained a kit, for making this connection. In the photo you see the "Backbone" cable with a node. The "tap" is contained in the cable clamp portion, and the MAU (Medium Attachment Unit) is a transceiver which converts signals on an Ethernet cable to and from AUI (Attachment Unit Interface). The AUI was a DB-15 connector.

Cris H

What's not true ?

In the late 80's the 10Base5 transceivers came with either a vampire tap or alternatively a type N tap with a type N coax connector at either end.

http://techmattmillman.s3.amazonaws.com/wp-content/uploads/2014/04/ST500-02a.jpg

http://techmattmillman.s3.amazonaws.com/wp-content/uploads/2014/04/AMP_221914-1.jpg

Dave "more commonly for those not trusted to terminate coax properly" what crud. The vampire tap system was the preferred method of tapping a live backbone! The kit consisted of 2 halves of the cable clamp, the tap its self, and an MUA/AUI. Oh, I almost forgot  the coring drill/tool (this shows a red installation device) Mine was a nice chrome T-handle affair. It should be in my tool draw, but it may have been tossed.  And just for grins what where all those black stripes on the cable, Oh, yes that's where they had to go.  Never closer than on strip away. "

And just for grins what were all those black stripes on the cable?

Oh, yes that's where they had to go.  Never closer than on strip away.

"Transceivers may be installed only at precise 2.5-metre intervals. This distance was chosen to not correspond to the wavelength of the signal; this ensures that the reflections from multiple taps are not in phase.[4] These suitable points are marked on the cable with black bands. The cable must be one continuous run; T-connections are not allowed."

Cris H.

From memory both N connector and vampire tap 10Base5 systems were used.

The N connectors weren't used as T connectors but as tap points into the segment effectively having the trunk as one continuous run.

TDRs were used to check the quality of the network installations. One could see the discontinuities.

To extend the Ethernet repeaters were used. Up to a maximum of 4, having a total of 5 network segments with 3 node populated segments and 2 unpopulated segments.

A maximum of 100 nodes could be installed on populated segments.

There were other horrible networking systems around where repeaters were not supported and the entire trunk had to be replaced if its length required extension.

MAU MAU MAU MAU!

But that's beyond the scope of this discussion.

Hi Cristina! Your posts send me back in the past...

Nice job. Enrico