• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Cat6 connectors worked but Cat 5e connectors did not for a Cat 6 cable that tested fine with both types plugs

Thread starter #1
I described this issue here
where I found that my Cat 6 buriable, waterproof cable (about 230' long) had been severed by a rodent.

Is there any difference between cat 5e and cat 6 RJ45 plugs for use with a Cat 6 cable?

I got Ideal Industries brand Cat 5e RJ45 plugs (Model # 85-346), like these:
(8-position, 8-contact RJ-45 modular plug for Cat 5e, 100Ω balanced twisted pair 100 MHz cables)
and a Cat 6 connector to connect the two pieces of cable, and attached the plugs to each end of the cable, and at the break, connected everything, everything tested fine continuity across all 8 wires, using both one of those flashing LED cheap testers, and also with a Southwire M400TP digital tester, which amounts to the same thing I believe, just with a digital screen:

Although everything tested fine, still I couldn't get data transfer between the two routers - the cables plugged in at each end would not turn the little LED light green to indicate data transfer, and the routers never recognized each other.

Then I went I got these Ideal Industries Cat 6 RJ45 solid plugs (Model # 85-367):
(Single piece Cat 6 connector same preparation as Cat 5e connector
Pair twists maintained within 1/4 in. -3/8 in. of pin contact)
and used the same Cat 6 connector to connect the two pieces of cable,
and replaced every plug with these, ran the tests again, everything fine, and now the data transmits and works fine.

Why would the Cat 6 plugs work any differently from the other? I am running under 300 Mbps speed.
Last edited:


Active Member
The Cat5e plugs should work fine with Cat6 cable, with sligh differences in specifications. That said, there may be slight differences in wire size, so make sure those plugs are a match for the wire size in the Cat6 cable.

I would suspect you mis-wired it or had poor crimps. Even with bad plug crimping, you usually get some indicator at one end of a switch or router. 100Mbps used only 4 of the 8 wires. Even if you had a wiring mistake, or bad RJ45 plugs, the wire should have connected at 100Mbps at least (odds are good you would still get 100Mbps).

Not sure why your tester showed continuity, but no signal. If any pairs are reversed, it would show continuity but Ethernet may fail to work properly.


Well-Known Member
Most Helpful Member
Reminder that there are three types of connectors. One for solid, stranded and both kinds of connectors.

You 5E connectors are solid and stranded and the CAT6 is solid, I think based on the data presented here. There is also a difference in wire gauge accommodated.

I don;t like the blinky things for end to end tests. They pretty much test what pins are connected where. I like the ones that used solid LEDs of differnet colors to indicate straight and cross. You can wiggle the ends and get discontinuities. Something you can;t get with the blinky things,

Then this http://www.idealindustries.ca/produ...&div=2&l1=kits&l2=kits_twisted_pair&l3=85-346

is wierd.

Includes plugs for round cable with solid conductors and plugs for flat cable and stranded conductors.

Looks like POT luck - some of each.

I never believe anything anymore.

The 5E connectors look like a repair kit, so if your not careful bad things happen. See datasheet; http://www.farnell.com/datasheets/1...54.1923204915.1545355689-611498244.1545355689

Bad things happened. Some worked and some didn't. What I would expect,

Didn;t do the exercise for your CAT6 ones.
Last edited:
Thread starter #4
Both plugs came in the exact same clear plastic housing. I wasn't aware that either package Model # 85-346 (Cat 5e) or Model # 85-347 (Cat 6) contained different types of plugs, as far as the packaging states, and what I could observe, there were 25 of the exact same plugs in each box.

Looking closely at the side, there were minor differences in the shape and perforation of the metal between the Cat 5e and Cat 6 plugs, but nothing much, and as noted above, the clear plastic housing of the two plugs was identical.

The back of the Cat5e plugs box writes, "use on solid or stranded"

and the back of Cat 6 plugs box writes, "compatible with 23 and 24 AWG"

The cable was:
AWG23 Solid-Bare Copper
Category 6 Shielded Twisted Pair (STP) Cable

In case I wasn't clear, both the testers showed a complete PASS in all respects just like this

for whatever these little testers could test, for both plug setups, but in the end only the Cat 6 plugs worked for data transfer (for the actual task) between the two routers.
Last edited:


Well-Known Member
Most Helpful Member
I use:

with an adapter I made that basically puts a remote on the end of it. It just consists of 4 bi-color LED's.

What I like about it, is that you can "wiggle" the cables and see bad connections. I have no idea where to get one now.

You can use a cable tester like yours to test for miswires. These seem to SLOWLY sequence looking for wiring errors. They won;t detect an intermittent contact. That seems to be more of an issue for me.
Last edited:


Well-Known Member
Most Helpful Member
did you perhaps get the wiring from one of the splice jacks to the other reversed? it does happen...
Although everything tested fine, still I couldn't get data transfer between the two routers - the cables plugged in at each end would not turn the little LED light green to indicate data transfer, and the routers never recognized each other.

where I found that my Cat 6 buriable, waterproof cable (about 230' long) had been severed by a rodent.
sorry, too obvious to resist.... you need 6 cats to get rid of your rodent problem...

however, i have squirrels biting through my antenna wires, so i've begun painting my antenna wires with habanero pepper oil... the real weird part here is they were trying to eat bare copper...

Is there any difference between cat 5e and cat 6 RJ45 plugs for use with a Cat 6 cable?
there shouldn't be much if any difference in the plugs, the difference is in the twist rate of the cable, and the uniformity of the twisted pairs. it's like the difference between standard HDMI cables and HDMI High Speed cables. the connector is the same, but the cable has improved characteristics.
Thread starter #7
The testers tested perfectly for all sections of the cable, for the two separate pieces of cable, and for the long pieces connected together, with the tests coming through the same and perfectly with all Cat 5e RJ45s, and with all Cat 6 RJ 45 plugs.

I did not use any splice jacks (if I understand what splice jacks are). I used RJ45 plugs only, and then connected the two plugs (the two pieces of cable) to each other using the same Cat 6 wall jack (coupler) in both setups. The wall jack (coupler) was this:

However, data transfer worked only with the Cat 6 RJ45 plugs. I tested data transfer with the Cat 5e plugs both all the way down the line, for the entire length of cable connected with the connector, and also for each individual piece of cable with the Cat 5e connectors without the coupler, and in all cases, where Cat 5e connectors were used, no data transfer - no data transfer with the individual pieces of cable, no data transfer along the entire length of cable. Basically, the Cat 5e RJ45 setups failed for all data transfer even though they passed all tests with the testers same as the Cat 6 plug setup.

The cable remains connected together and is still working fine with the Cat 6 plugs. All I did was get rid of that split hosing coupling, and just leave the buriable, waterproof cable itself right above the ground. (I covered the patch area with a length of heat shrink tubing and duct taped each end of the tubing.) So far, no rodent bites. :)
Last edited:


Well-Known Member
Most Helpful Member
the only thing i can think of that might be different is the side profile of the pins... looking at a cat5e connector from the side i can see the profile of the pins, and the main body of the pin has the same surface area as a 1608 size resistor, and the part that makes contact with the wire, about half that, so a total of 1.92 sq-mm. if i had to guess there's about 2 to 4pf capacitance between each pair of pins. up near 1Ghz, that's a lot of capacitance. so the cat6 pins are either thinner (so, more distance between surfaces of parallel pins) or somehow smaller in surface area in order to minimize the capacitance... i'll have to see if i can find a cat 6 cable for comparison.


Active Member
I'd think it's simply cable <> plug <> tooling compatibility.

We used to build our own Ethernet patch leads at one time.

Even with extremely expensive crimp tools, we had poor reliability both in terms of immediate function and failures over time.
There are many types of plug, each needing different tooling to work well, plus different plug variations for single core or stranded cables.

A tool that works OK with one batch of plugs may not work with another batch that are supposedly to the same pattern.

We also found some type of socket/jack (with open terminals) to have poor long term reliability.

Our rule now is that we only use commercial ready made patch leads and always use CAT6 keystone jacks on trunk cable, we simply never fit a plug to anything.
That has eliminated all problems other than the occasional faulty as received plug to plug cable - which is pretty obvious when setting up an installation in the first place, it's not a reliability issue.

This general style of socket, which have a cable strain relief and can also be used as free sockets if needed:
The same thing can also be used in both patch panels and wall plates, so less things to stock.

I'd highly advise using only sockets when terminating cables, unless it's a mass production setup where tooling and parts come from the same manufacturer and you have direct support from them.
Thread starter #11
The replacement cable that is coming, the rodent proof Cat 6 encased in stainless steel, has the plugs at each end already fitted.

but for now, until it gets here, what I have patched with my own Cat 6 plugs is working fine.

Couple reasons I got the non-terminated cable before, were because I wasn't really sure how long of a piece I needed (now I know, from measuring the line along the path of what I have laid), and to get the cable in have to make bigger holes when the cable has the plug already attached.

Also, I have heard that if you drag along the cable that has a plug already on it, while running the line, it may ruin the connection.


Well-Known Member
Most Helpful Member
Also, I have heard that if you drag along the cable that has a plug already on it, while running the line, it may ruin the connection.
Totally obvious if it snags. Pulling can also pulls off the tab.

@rjenkinsgb has a lot of good design practices. Using only Keystone jacks in all patch panels is also a good idea.

I a;so agree with the tooling. I had an AMP tool that really only worked with AMP connectors.

The EZ-RJ45's https://www.platinumtools.com/products/connectors/ez-rj45-cat6-connectors-100010c/ are really easy to terminate.

I also use the strain relief: https://www.platinumtools.com/products/connectors/ez-rj45-cat6-strain-relief-100036/


Well-Known Member
Most Helpful Member
i was able to get a cat6 and a cat5e cable to look at side-by-side. it looks like the pins/inserts on the cat6 connectors are thinner, which would increase the spacing and reduce the capacitance.


Active Member
I do not believe connector capacitance is anything to do with the problem - an inch or two more or less cable would have more effect on capacitance.
Most likely it was just that the plugs were not fully compatible with the cable in use; there are (or were) two fundamentally different types for stranded or solid cable.

The stranded ones had central points below the contacts, so the wire was pierced through and compressed sideways.
The single-core ones had offset teeth that gripped the sides of the wire conductor when crimped.

Use the wrong type and the connection is likely to be unreliable, if it works at all - eg. the centre point for stranded wire can cut through a single core & the "grip" teeth cannot put enough pressure on a stranded wire than can reshape itself.

And even with exactly the correct plug and tooling, they were never 100% reliable as I mentioned before.

EE World Online Articles