About CAT-5 for 2 phone line and ethernet

Archived from groups: comp.dcom.lans.ethernet (More info?)

praveen <praveenkumar1979@rediffmail.com> wrote:
> I am planning to use CAT-5 cable for carrying 2 phone line
> and a ethernet data.

> I am running this cable for about 50 meters.I am using 10
> Mbps ethernet data.

Cat3 is good enough for this service, and it was designed
specifically for this shared-sheath service. Nowadays,
people prefer to run separate cables. 50m is well within
spec (100m), but you seriously risk lightening damage if
it is run between buildings.

> I wanted to know type of interference that will occur.

Some phones installed can draw high current during ringing,
which _might_ interfere with ethernet. I would be suspicious
of old mechanical-contact bells/buzzers. But even these should
only ruin a few frames, and ethernet has to be designed for
collision-damaged frames.

> Is there any method by which i can reduce the interference.

Yes. Make _sure_ you do not split any pairs (wire correctly).
Twisting is done to balance interference and reduce net noise.
Paired signals must travel on paired conductors.

-- Robert

Archived from groups: comp.dcom.lans.ethernet (More info?)

praveen wrote:




> Hello,
> I am praveen Kumar.
> I have a problem in CAT-5, can you please give a feedback.

> I am planning to use CAT-5 cable for carrying 2 phone line and a
> ethernet data.

> I am running this cable for about 50 meters.I am using 10 Mbps
> ethernet data.

> I wanted to know type of interference that will occur.

> Is there any method by which i can reduce the interference.
> As ethernet data is using error correction method ,Can phone line
> really create problem to ethernet data during ringing?



> Waiting for reply
> Thanks and regards
> Praveen

You can certianly do that, although it would not be a good idea to base a
100-outlet network on this kind of design. A cable that's split like that
between three jacks is not going to support Gigabit Ethernet, which you
may want going forward in the future. Make sure you leave pairs #2 and #2
(orange and green) connected to the data jack,first line on the blue pair
and second line on the brown one.
The rings are not going to create any problem as the fre


--
Dmitri Abaimov, RCDD
http://www.cabling-design.com
Cabling Forum, color codes, pinouts and other useful resources for
premises cabling users and pros
http://www.cabling-design.com/homecabling
Residential Cabling Guide
-------------------------------------





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Archived from groups: comp.dcom.lans.ethernet (More info?)

praveenkumar1979@rediffmail.com (praveen) wrote:
>This is used for commerical use. So i need more information about the
>interference.

If it's for commercial use, follow the standards and pull another
wire. More wire is always cheaper than non-standard installations in
commercial applications.

Archived from groups: comp.dcom.lans.ethernet (More info?)

Dmitri(Cabling-Design.com wrote:

> praveen wrote:
>
>
>> This is used for commerical use. So i need more information about the
>> interference.
>
> If by saying "for commercial use" you actually mean that you are worried
> about liabilities, then you should just abandon the idea of splitting the
> cable and go by the cabling standard for commercial buildings -
> TIA/EIA-568-B that specifically disallow cable sharing.

Does it explicitly disallow sharing or does it simply require that the
premise wiring be jack to jack with all conductors of a specific cable
terminated on a single jack and any sharing done using splitters that are
plugged into the jacks and thus outside the scope of the standard?

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

Archived from groups: comp.dcom.lans.ethernet (More info?)

praveen wrote:

> Hello,
> I am praveen Kumar.
> I have a problem in CAT-5, can you please give a feedback.
>
> I am planning to use CAT-5 cable for carrying 2 phone line and a
> ethernet data.
>
> I am running this cable for about 50 meters.I am using 10 Mbps
> ethernet data.
>
> I wanted to know type of interference that will occur.
>
> Is there any method by which i can reduce the interference.
> As ethernet data is using error correction method ,Can phone line
> really create problem to ethernet data during ringing?

Twisted pair ethernet, was originally designed to use existing phone
cabling, which means it was built to tolerate the signals found in a phone
system. Also consider the frequencies involved. An analog phone line
operates at frequencies below 4 KHz, with ringing usually at 20 Hz. In
comparison, 10baseT uses signalling at between 10 and 20 MHz, which is at
least 2.5 thousand times the frequencies used in the phone system. The
coupling transformers in the network cards are designed to efficiently pass
the ethernet signal, but not the phone signals. This means that
interference is unlikely.

Archived from groups: comp.dcom.lans.ethernet (More info?)

SyncMan wrote:

> Do not carry POTS and Manchester coded data together
> although it does work in the lab here.
> I tried this just for fun and I did get an effect on our 75meter
> run using 10baseT and just the one POTS 90Vrms 10Hz
> ACD ringdown and it worked OK. But I know there are risks
> on induced voltages and NIC's would fry for sure.

While 90V ringing would certainly cause problems, if connected directly to
the NIC, the transformers that connect the line are supposed to handle a
few hundred volts, without creating a safety problem (that doesn't mean no
equipment failures).

> Again, I did this just for curiosity but 568 specifically mentions
> separation of services. NICs are just not FCC part 15/68 DOC CS03
> and they are definately not ready for those voltages. POTS lines
> may come from outside the dwelling where all sorts of high
> energy discharges exist including Lightning. Yikes.
> If something happens,
> damages will occur and
> there is a risk to Human contact
> where future maintenance crews were not expecting the hazard.
> Up here in Canada, that would be considered as a "man-trap",
> and can result in manslaughter charges against designers
> or installers of the hazard should a death occur.

Twisted pair NICs originally were originally designed to share phone
cables. While it's not considered good practice to combine the two on one
cable, there are occasions, when it's necessary.

Also, phone cables coming into a building, must have protection against
surgers. That said however, a close enough lightning hit, is going to
cause problems, no matter what. Incidentally, many computers are connected
to the phone line through dial up and DSL modems.