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I am looking for a replacement for an RJ45 panel mount connector. Can I use any standard connector (picture below) for connecting Ethernet networks?

enter image description here

I know about cable impedance matching but I was wondering if the connector's contacts have any effect on the line's impedance. So I searched dozens of RJ45 panel mount connectors datasheets(such as this datasheet) to find that the impedance is not even mentioned.

Edit:

Since people are asking questions about the reasons for replacing the RJ45 connector:

  1. There is another RJ45 connector and I want to prevent plugging the cable into the wrong connector
  2. I listed the mini DIN as an example (We use this connector so its stocked and really cheap) but the question is generally about using a non modular connector to connect an Ethernet network.

Some Conflicting answers:

The connector has a matched impedance even though its not stated in the datasheet because it's so obvious

VS

Its meaningless to ask for the impedance for a connector. It has no capacitance or inductance

Correct me if I'm wrong but I think The second answer is correct. I will surely use a CAT5e cable and shorten the mini-DIN connector's wires minimizing the length of the unraveled cable. I guess this should work...

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    \$\begingroup\$ How available are miniDIN to RJ45 cables for your custom ethernet pinout? \$\endgroup\$ – user2943160 Aug 27 '16 at 14:34
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    \$\begingroup\$ Rj45 is a standard connector... \$\endgroup\$ – Passerby Aug 27 '16 at 20:31
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    \$\begingroup\$ In order to specify an impedance, the impedance needs to be referenced between two elements. The Ethernet pairs on a RJ45 are 1-2, 4-5, 7-8, which are adjacent. The remaining pair 3-6 skips two pins. This alone tells you that the impedance through the RJ45 connector system cannot be uniformly close to any one particular impedance. I think if you cut off essentially the length of the pig-tails wires and connect the twisted-pairs directly to the connector body, it should work. But I wonder along with others as to why (abandoning the advantages of a standard proven arrangement). \$\endgroup\$ – rioraxe Aug 27 '16 at 21:00
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    \$\begingroup\$ Please see this also: electronics.stackexchange.com/questions/212917/… \$\endgroup\$ – rioraxe Aug 27 '16 at 21:02
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    \$\begingroup\$ You should be able to get 8P8C connectors with an offset latch. Also, if you colour-code the cable and the socket (maybe just the surround) then people will get a big hint as to what to connect where. \$\endgroup\$ – Andrew Morton Aug 28 '16 at 15:47
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You would only be able to answer this by examining the return loss and crosstalk if using duplex mode for the distance you need. Given that RJ-45 come with ferrite common mode filters as an option, you would lose this noise improvment. When choosing a connector, beware that this is one of the most common types and your ability to locate them is limited only by your awareness of distributors.

Characteristic impedance is geometric property of conductor spacing and thickness or in coaxial inner OD/ID for a given dielectric constant. This defines the distributed inductance to capacitance ratio which is a function for impedance that must be matched to each 110 Ohm line.

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    \$\begingroup\$ how can i examine the return loss? And should I really measure the crosstalk of the connector as I though that capacitance between contacts is negligible. \$\endgroup\$ – fhlb Aug 28 '16 at 2:45
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    \$\begingroup\$ Its not just your conn. but choice of cable, splices, baluns, layout, etc that may cause issues at 100MHz ,with your awareness of transmission properties. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Aug 28 '16 at 4:46
  • \$\begingroup\$ OP is not looking to convert from balanced to unbalanced so baluns and co-ax have low relevance here. \$\endgroup\$ – KalleMP Sep 15 '16 at 22:35
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As you're first question is a replacement for a panel mount RJ45 plug. And if you don't want to have any problems with you're connection I would suggest to have a look at the M12 circular connectors according to the IEC 61076-2-109 standard.

The X-coded variant is able to transmit at rates up to 10Gbps. They are broadly available from various manufacturers. And have all sorts of variants with panel mount connectors. Converter cables back to RJ45 plugs.

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    \$\begingroup\$ +1 Very nice connectors and would be my choice to avoid the rather tacky 'telco' connectors that are used just to same money. However in this case OP cited connector sourcing problems and these may be even harder to get hold of in some outlying location. The miniDIN panel mount is not that common either but at least OP has some source of supply in mind. \$\endgroup\$ – KalleMP Aug 28 '16 at 19:13
  • \$\begingroup\$ @rfkortekaas why donot you provide a link ?\ \$\endgroup\$ – ElectronS Aug 29 '16 at 7:23
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    \$\begingroup\$ @ElectronS there are a lot of suppliers delivering this connector so that would be a hugh list with only off-site resources which are likely to change. Searching on the Internet for the IEC standard or M12 X-Coded provides all the up-to-date details. \$\endgroup\$ – rfkortekaas Aug 29 '16 at 16:05
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I expect it would work with short jumper lengths at CAT4 (10 Mbps) speeds.

Remember that at 100 Mbps you have to have very careful PCB design, the flyleads in the picture above would have to be carefully and evenly twisted to match the cable impedance and terminating them on the board would have to be done carefully.

You would also have to use good low capacitance twisted pair cabling with your MiniDIN flyleads to get any kind of jumper distance.

Basically I think you would have a hard time getting it to work well.

If you can get cheaper RJ11 or RJ12 panel mount connectors you could perhaps save a bit there but you would still need to terminate your good CAT4/5 cables to the phone connectors to go any distance. CAT6 1000 Mbps links use 8 pins to get full benefits of duplex transmission so you would be limited to lower speeds automatically by just using two pairs.

The above may be generalising a bit but should give you the idea that it may not be very practical.

Unless you are wanting to hide the fact that it is a UTP port on the box :-)

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    \$\begingroup\$ for 10Mbps, connector's wires shortened, use of a cat5e cable with an RJ45 connector inside the box. Everything should be ok now? \$\endgroup\$ – fhlb Aug 28 '16 at 2:49
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    \$\begingroup\$ The cost of testing will be low. If it sometimes works at 100Mbps then it might work most of the time at 10Mbps. There will be no way t guarantee the functioning but modern hardware is pretty awesome in spite of poor signals if there is enough for the electronics to amplify. \$\endgroup\$ – KalleMP Aug 28 '16 at 19:10
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Yes, you could probably use that mini-DIN connector for low-speed (10MB or lower) network connections. But since it is not designed to maintain any kind of impedance control, you would be risking intermittent performance (or possibly completely dead) at higher speeds.

The reason regular 8P8C (incorrectly called "RJ-45") don't mention impedance is because you can assume that they are properly designed for the 110 ohm impedance used by 10BASE-T or 100BASE-T internet connections.

Absent the context your statement that the proper 8P8C connector is "unavailable" seems very odd. If you put a non-standard network connector on your unidentified gadget, you will then have the problem that a mating network cable will also be "unavailable" since nobody makes such a thing. Anywhare on the planet.

Ref:

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    \$\begingroup\$ Similar comment like the one above. Why do people insist that nobody on the world needs custom stuff? I also searched some time and than went for a small connector from samtec to have a pluggable, small size ethernet solution without the huge standard connector. Sometimes solutions are not standard. That's it. \$\endgroup\$ – Junius Aug 27 '16 at 22:44
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    \$\begingroup\$ @user3796486: Because custom stuff is an absolute pain. Even RS-232 serial cables, for example, were a mess of male / female / straight-through / cross-over and the total amount of lost time suffered in the world trying to make stuff talk due to non standard communication must have been immense. I had to make up leads for RS422 on Mitsubish PLCs using the OP's connectors and they were a pain. Nobody will thank the OP for that solution. \$\endgroup\$ – Transistor Aug 27 '16 at 23:55
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    \$\begingroup\$ When it comes to connectors, RS422 and RS485 networks are like the vendor's thumbprint. \$\endgroup\$ – fhlb Aug 28 '16 at 2:20
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    \$\begingroup\$ @Transistor: I totally get your point and personally, I like it when things are standardized! I just wanted to say that sometimes (as it was the case for me) you just don´t have a choice ;-) \$\endgroup\$ – Junius Aug 28 '16 at 12:57
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Molex's datasheet didn't specify the characteristic impedance because the RJ45 socket has nothing to do with matching the impedance (unlike coax RF connectors). One advantage of modular connectors is that a connection does not require untwisting a large portion of the cable. So you should make sure to keep untwisted section as short as possible and your setup should work.

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