How to terminate CAT 5 cable with RJ45 for ethernet

A

Thread Starter

Anonymous

hi all

i need to make a small network of 3 computers, and an adsl router.

the cables run in a wall, and im using cat 5 cable, is it good?

i am trying for the first time to terminate the cable by myself, i am using T568A color standard as I read in the net.

And there is 1 thing I cant find an answer to!!!

the cable has a foil around the twisted pairs, and the RJ45 Connector is covered with metal, should these two be connected?

from my understanding the connection between them will insure the the foil would be grounded, is that good?

and 1 more Q: May I run the cat5 cable outside the building, between 2 floors?

btw: I do not use wall jacks

10x!!!!!!!
 
For outdoor network runs, i suggest optic fiber. You can just use 2 fiber to copper converters, and youi could maybe find some prefab terminated fiber cables, with the required length.
 
im not too sure about the cable you are using, it seems like it is Shielded Twisted Pair. I would use some sort of conduit if you ran the cable outside of the building.

just my .02
 
N

nedohin-macek

cat 5 is good and fairly easy to work with from small LANs such as what you are talking about.

The foil around the twisted pairs is for shielding in high electrical noise environments. You would generally connect this to the chassis of the computer you are connecting the cable to. Often this is not required in home and office applications where there is no large machinery starting and stopping all the time.

You can connect the foil to the metal connector cover if you want because the metal connector cover will undoubtedly touch the chassis of whatever card it is plugged into. But you should only connect ONE end of the cable foil to ONE connector cover. This will avoid any problems with ground loops if your two device grounds are at different potentials (grounding of one building circuit is different than the grounding of another building circuit).
I wouldn't bother with connecting the foil to the metal connector cover in a home or office application, but I definitely would in a high noise environment (again, connect the foil to only one end).

As for running the cable between two floors, you should ensure that it is covered with some conduit of appropriate type (say a 1" pipe -PVC or otherwise) to protect the cable from the weather. If your cable is being strung between two buildings or otherwise strung in such a way as to make a nice place for birds to sit or squirrels to run across, you will need to consider running some rope so that the cable doesn't hold the weight of what ever is sitting on it.

Julian Nedohin-Macek
Winnipeg, Canada
 
B

Bill Clemons

Category 5 cable (Unshielded twisted pair, multiple) should not require shielding of any type. Terminating cable to RJ45 jack requires special tooling and decide whether to run cross-over, straight-run, A or B. You should reconsider your network connection requirements if you find yourself connecting any type of shielding, cable or braid, to your category 5 cable.
 
Strip the cable with proper cutter or stripper max 3''.

Then remove the twist as per folloing sequence

1.Orange pair - white cable
2.Orange pair - orange cable
3.Green pair - White cable
4.Blue pair _ Blue cable
5.Blue pair _ white cable
6.Green pair - Green cable
7.Brown pair - white cable
8.Brown pair - Brown cable

ALso make the cables straight & cut the ends ( Cable should be max 1'' fm the insulation )perperly & insert inthe RJ 45 conector & press is formly once.

Regards

Shripad
 
E

Eric Apperley

1. Cat 5 cable is normally UTP (unshielded twisted pair. There are two versions, one for fixed infrastructure wiring in buildings (solid core) and one for patch leads to equipment (stranded conductors).
2. You should install wall sockets and use solid conductor Cat 5 UTP cable between those wall sockets and a socket adjacent to the router. The alternative is to buy long patch cables (e.g. 30m to 50m) and use those directly bewteen the PCs and the router.
3. The total physical Cat 5 cable length between devices on the network (e.g. PC and router) must not exceed 100m. With patch cables and wall sockets the implication of this is that the fixed infrastructure wiring should not exceed approx 90 metres (that allows a 5m UTP patch cable at each end between the wall socket and the equipment (PC or router).
4. It is not sound engineering practice to run solid core cable directly into PC's or the like. The reason is that PCs can tnd to get moved and solid core cable is not designed for moving.
5. Note that there are different versions of the UTP plugs - one for stranded conductors and a different one for solid conductors.
6. Generally there should be no need to use shielded cables in buildings unless there are electrically noisy devices (electrical impulse type noise, ew.g. large motors or contactors etc) situated in close proximity to the UTP cables.
[As a general rule for shielded cables you should only ground shields on cables at one end only - this prevents ground currents flowing along the sheath.]
7. UTP cables should be segregated from power or analog telephone cables by at least 50mm (2").

Eric
 
> the cable has a foil around the twisted pairs, and the RJ45 Connector is covered with metal, should these two be connected?

Ignore the shield connections and use the cable. If it works you're done.

Next try wraping a small magnet in aluminum foil and sticking it on your refrigerator.

"Shielding and grounding" is a black art.
 
G
Most RJ45 connectors are not metal encase, but plastic, so the grounding is irrelevant. As for running between two floors, I have connected my computer upstairs to my daughter's computer downstairs without the aid of wall jacks via a 4 port switch so we can connect to a common cable modem.

Wall jacks are merely a means to terminate. In a relatively noise free environment, 100 ft of cat5 is nothing to worry about. Go for it.
 
F

Fred Townsend

On August 12, 2003, Anonymous wrote:
> hi all
>
> i need to make a small network of 3 computers, and an adsl router.
>
> the cables run in a wall, and im using cat 5 cable, is it good? <

Yes this is good.

> i am trying for the first time to terminate the cable by myself, i am using T568A color standard as I read in the net. <

This is good too. Just be consistent.

> And there is 1 thing I cant find an answer to!!!
>
> the cable has a foil around the twisted pairs, and the RJ45 Connector is covered with metal, should these two be connected? <

Sorry! Cat 5 cable does not have a shield.

> from my understanding the connection between them will insure the the foil would be grounded, is that good? <

No. This may cause problems. Perhaps you could away with grounding at one end. Then again this may be a code violation in some places. I'd get "real" UTP cat5 or cat 6 cable.

> and 1 more Q: May I run the cat5 cable outside the building, between 2 floors? <

Network systems are not protected for lightning nor is CAT5 rated for direct burial. I would use fiber, IR, or microwave extenders if I were running between buildings.

Fred Townsend
 
Something wrong here!!! Cat5 cable does not have a shield. Neither does Cat5E or Cat6 cable. Cat7 cable is not really standardized yet, but does have a shield for each pair and an overall shield. Most instrumentation grade plenum cable has shielded twisted pair, with an overall shield, but is not recommended for Ethernet use. You cannot get a good connection to aluminized Mylar used as a shield, so there is usually a bare copper wire in contact with the aluminized side of the foil, and that should be used for grounding.

Siemens and others sell a wire called Industrial Ethernet cable that is shielded and is of the right impedance to be used for Ethernet. It is not Cat5.

Dick Caro
============================================
Richard H. Caro, CEO
CMC Associates
2 Beth Circle, Acton, MA 01720
Tel: +1.978.635.9449 Mobile: +1.978.764.4728
Fax: +1.978.246.1270
E-mail: [email protected]
Web: http://www.CMC.us
============================================
 
P

Peter Whalley

Hi all,

Standard Cat 5 cable does not have a shield but versions of Cat 5 are available with shield. Some markets demand this particularly Germeny and some military users. Shielded Cat5 connectors are also available if needed.

What you do with the shield is a good question however. You can connect it at both ends provided the earth potential difference is small enough (say less than 0.5 V RMS).

Remember IBM Type 1 cable. Shieled and connected at both ends but when you read the fine print in the IBM application guides it says that earth potential difference must be less than 0.5 volt.

I have also run shielded Cat 5 as backbone cable in a 10 level office building running 10BaseT without problem but maybe we were lucky.

A military client of mine some years ago was required to use shielded cable for security reasons but every security inspector that came out to approve their installations had different requirements about what to do with the shield. Eventually they gave up and decided to use optical fibre to the desk for all new installations.

The US market was subjected to some very strong FUD marketing about shielded Cat 5 because the major supplier didn't have a shielded product in their range. The German market is forced by regulation to use shielded cable exclusively and manages to make it work regardless.

One approach is to ground the shields at both ends via a parallel combination of 470ohm resistor and 0.1uF capacitor. The resistor is high enough to prevent hum loops at low frequencies whilst still bleeding of any static charges and the capacitor shorts out at high frequencies to provide a mesh grounding effect. Has anyone out there used this approach.

Regards

Peter Whalley
Magenta Communications Pty Ltd
Melbourne, VIC, Australia
e-mail: peter*no-spam*@magentacomm.com.au
delete *no-spam* before sending
 
> Strip the cable with proper cutter or stripper max 3''.
>
> Then remove the twist as per folloing sequence
>
> 1.Orange pair - white cable
> 2.Orange pair - orange cable
> 3.Green pair - White cable
> 4.Blue pair _ Blue cable
> 5.Blue pair _ white cable
> 6.Green pair - Green cable
> 7.Brown pair - white cable
> 8.Brown pair - Brown cable
>
> ALso make the cables straight & cut the ends ( Cable should be max 1'' fm the insulation )perperly & insert inthe RJ 45 conector & press is formly once.
>
> Regards
>
> Shripad
 
Dear all,

I am designing a voice/data/video network for a building which is in a relatively noisy area. It is very close to the harbour with Radar units in it proximity. The client wants to go for CAT6. Do you think that i need to go for the shielded type of cable because of possible interference from surroundings?

Thanks a million.
Alexandra.
[email protected]
 
P

Peter Whalley

Hi Alexandra,

Very hard to answer that without knowing exactly how strong the EMI is in the building.

Cat 6 will give better protection than Cat 5 and shielded Cat 6 MAY give better protection yet again. If you have a real problem then you could go to Cat 7 (individually shielded pairs plus an overall shield but very expensive and difficult to install and uses non standard connectors).

It will also depend on what you want to run over the cable (now or in future). 10BaseT will withstand just about anything if run over Cat 6 but 1000BaseT is likely to be much more sensitive to interference because it uses higher frequencies and the twisting of the pairs is less effective at higher frequencies.

One approach is to contact your local Systimax Solutions http://www.systimax.com/ office and ask them if they would certify the installation in the building. They may be willing to do some tests (either free or at a charge) to determine if they will. I did have some comments from Systimax (Lucent at the time) years ago about doing such measurements. Systimax (and possibly a few of the other majors) have the head office
technical resources to answer such questions.

Regards

Peter Whalley
Magenta Communications Pty Ltd
Melbourne, VIC, Australia
e-mail: peter*no-spam*@magentacomm.com.au
delete *no-spam* before sending
 
F

Fred Townsend

There may be very good reasons, such as robustness, for using CAT6 but I don't think that immunity from radar is one of them. I would make sure everything was going into steel conduit and use NICs with good common mode rejection if I thought noise was going to be a problem.

Fred Townsend
 
Alexandra,

CAT 6 cable is not shielded. See
http://www.tiaonline.org/standards/category6/
It is specified for higher frequency response than CAT 5e, but not for improved interference rejection.

Siemens recommends using their Industrial Ethernet cable which is a shielded form of CAT 5 for high interference situations. CAT 6 cable was created for Gigabit Ethernet that demands 250 MHz frequency response for each pair.

Dick Caro
============================================
Richard H. Caro, CEO
CMC Associates
2 Beth Circle, Acton, MA 01720
Tel: +1.978.635.9449 Mobile: +.978.764.4728
Fax: +1.978.246.1270
E-mail: [email protected]
Web: http://www.CMC.us
Buy my book: Automation Network Selection
http://www.isa.org/rd.cfm?id=3573
============================================
 
G

Gerald Beaudoin

Computer installations near sources of radar energy generally employ shielding all around the building..... such as fine wire mesh in all walls and curtains for the windows. Anywhere near an airport would be such a place. Putting everthing in steel conduit also is a good approach. Pulsed radar in the megawatt power range puts out a pretty strong RF field..... if you are in the line of sight.... and no shielding...... count on problems.

Gerald Beaudoin
 
E

Evil Brewmaster

I have a string hunch you do not want to have the foil that's wrapped around the cable in a position where it can cause a short or leak, as its main pupose is to shield the cabling inside the jacket.
 
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