Intermittent connection

[JuzzyD]

Hi, I've just been to a site where one building has an intermittent connection to the network - if I ping the server sometimes I will get a reply 4 times in a row, others maybe 2 or 3 times.

Cable length I would imagine is about 80 metres from the hub.

I assume that it must be down to signal loss - does anyone know of a suitable "booster" for a single cable?

Thanks in advance.

 

[DToolsDesigner]

Tell me more about the components in the link between buildings. What kind of jacks, cable, patch cords, solid or stranded conductor, cat 5? Are the patch cords field constructed or factory made? Have you run a certification tester on the link?

My first thought whenever I here of intermittent connections is field constructed patch cords made with the wrong type of plugs.

A solid conductor cable with plugs made for stranded cable will certainly cause intermittent connection problems.

 

[JuzzyD]

The cable between the buildings is solid core - the hub end is crimped straight into a plug, the remote end is to a wall jack - both ends are secure. A standard 1 metre patch cable then runs from the wall jack to the PC.

The cabling checks out fine with a tester, all wires connected correctly.

Whats the difference between a plug designed for solid cable and one designed for stranded?

Thanks for the reply!

 

[skip555]

- the hub end is crimped straight into a plug

I would terminate it to a jack and try a standard patch cable


Whats the difference between a plug designed for solid cable and one designed for stranded?



the plug for stranded cable has teeth that come straigt doen and peirce the cable

the plug designed for solid cable has teeth that come down on each side of the solid wire bridging it

 

[skip555]

just wanted to add

if you look at the plug solid wire plugs are concave on the bottom of the slot that the wire goes into

stranded wire plugs are flat.

 

[DToolsDesigner]

A plug designed for stranded pierces through the center of a conductor, the solid straddles it, (grabs the sides) as they displace the insulation. So if you used a stranded on solid, it can and usually does, break the solid conductor. I learned the lesson the hard way to buy factory made cables, when my supplier sold me the wrong plugs and I had a huge mess on my hands with 45 drops. Since then I don’t crimp my own plugs except on rare emergencies.

Not uncommon to get a good reading one moment, and fail the next. Wiggle the plug between tests, or while testing.

The standards use to forbid field construction of patch cords just for this reason, that and anytime you have a plug on a solid conductor you will usually have reliability problems, as you are experiencing.

Solid conductors weren’t meant for use in places where flexibility is important.

The 80 meters is pushing it, but within standards, so i don't see that as the problem.

 

[JuzzyD]

Thanks. I'm sure the plug is the correct type from the descriptions above.

At no time when I was testing did the cable ctually fail - all lines remained connected even while wiggling the cable.

One interesting thing to note, and this is why I thing it may purely down to loss, is that when I changed the NIC in the machine the drops on the pings decreased.....

Is it possible to "up the voltage" a bit as it were?

 

[DToolsDesigner]

In a word...NO.... if changing the NIC alleviates the problem, even partially, I would not be so quick to suspect the cable.

You never mentioned the type of cable...Cat 5, 5e, 6?

 

[JuzzyD]

Its Cat 5.

I've tried the cable on different ports on the hub, even swapping with known "good ports" with no success.....

 

[skip555]

{b]Is it possible to "up the voltage" a bit as it were{/b]

put a hub or switch in line before it reach's the pc in the second building

you could also use this to troubleshoot as you could see if you still had a link light when you werent able to coneect.

 

[JuzzyD]

I had thought of adding a hub n between the buildings - the cable runs through another building on its way.

Come to think of it, the cable runs under the main power distribution setup in the third building - might be getting interference.

Anything I could do to check for this? Unfortunately it would be a nightmare to re-route the cable as I would have to dig up my clients patio......

 

[DToolsDesigner]

FYI...it is possible to have a link light and still nnot be able to transmit data. You only need 1 pair for a link light, but 2 pairs (10BaseT & 100BaseT) to transmit AND receive data.

You have starting at yout NIC, a 1 mtr patch cable...A Cat 5 jack, 80 mtrs of cat 5 solid condutor cable, crimped with a 8P8C plug directly into the hub? is that correct? Nothing else involved?

 

[JuzzyD]

As far as I can see yes, the cable runs through a duct in the ground between the buildings - I can't see a join in it where the cable can be seen.

The cable tests OK, all cables are making a link.

I tried my laptop on the connection with similar results, intermittent pings (sorry, forgot to mention that earlier). I even tried setting the link speed etc manually but that did'nt help (had experience before where a NIC could'nt decide what setup to use).

 

[skip555]

The cable tests OK, all cables are making a link.



so there are other cables in the building in question that are working ?

if so can you run a hub or switch of off one of them to the problem PC ?

 

[DToolsDesigner]

What certification tester did you use on the cable?

What was the attenuation/insertion loss reading?

 

[JuzzyD]

When I said cables I meant the pairs in the cable....there are two cables, both with the same problems, in the building.

I can't remember the make of the tester but it only has lights to confirm the connections - it does not give loss readings unfortunately.

 

[DToolsDesigner]

Well, without that level of testing, you have no way of knowing what you are dealing with. Where are you located? Anyone in your area that can run a true certification test on it?

A wire map tester such as you describe, can't even tell you accurately if you have split pairs, since they only read pin to pin.

FYI...Testing with a wire mapper is in my opinion only a precursor to certification testing, so you know it is terminated properly before you bring out the expensive test equipment.

 

[skip555]

your testing method is not really telling you much of anything

if you have access to the cables as they run through the 2nd building I would cut one cable terminate it to a jack and test with the laptop if the problem goes away then slap a hub on as a repeater and see if that clears the problem

if the problem still exists then you may have to pull new cable from bldg two to 3

 

[JuzzyD]

Thanks, I'll have to check out about certification testing over here (I'm in the UK).

If I can get enough slack on the cable I'll try breaking the connection and see what happens - its not going to get any worse anyway!

Thanks for your help. As an aside, can you recommend a good tester or suggest what sort of things I should be looking out for please?