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cross interference?

I've just run over a hundred feet of Cat-5e cable with no problem.  I 
believe it's unshielded ( 
http://www.insigniaproducts.com/products/computer-speakers-accessories/NS-PNW5525.html 
).

I'd also like to run the same length of 4 conductor flat (modular?) 
cable (phone extension) along the same path and the simplest way would 
be right on top of the Cat-5e run.  But I'm thinking I might get cross 
interference if I do.  Is that right? If so, what should be the distance 
between the two lines.
0
M
11/10/2015 7:43:15 PM
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In article <n1th8c$au3$1@dont-email.me>,
 "M. John Matlaw" <nouser@invalid.com> wrote:

> I've just run over a hundred feet of Cat-5e cable with no problem.  I 
> believe it's unshielded ( 
> http://www.insigniaproducts.com/products/computer-speakers-accessories/NS-PNW5
> 525.html 
> ).
> 
> I'd also like to run the same length of 4 conductor flat (modular?) 
> cable (phone extension) along the same path and the simplest way would 
> be right on top of the Cat-5e run.  But I'm thinking I might get cross 
> interference if I do.  Is that right? If so, what should be the distance 
> between the two lines.

If the Cat-5 is carrying just an Ethernet circuit, there are two "spare" 
pairs there already. Why not use those?

Otherwise, why not just another run of Cat-5? Unlike the telephone 
4-wire, the pairs are twisted, which will help to keep interference both 
in, and out.

Isaac
0
isw
11/11/2015 5:21:42 AM
isw <isw@witzend.com> wrote:

> In article <n1th8c$au3$1@dont-email.me>,
>  "M. John Matlaw" <nouser@invalid.com> wrote:
> 
> > I've just run over a hundred feet of Cat-5e cable with no problem.  I
> > believe it's unshielded ( 
> > http://www.insigniaproducts.com/products/computer-speakers-accessories/N
> > S-PNW5 525.html
> > ).
> > 
> > I'd also like to run the same length of 4 conductor flat (modular?)
> > cable (phone extension) along the same path and the simplest way would
> > be right on top of the Cat-5e run.  But I'm thinking I might get cross
> > interference if I do.  Is that right? If so, what should be the distance
> > between the two lines.
> 
> If the Cat-5 is carrying just an Ethernet circuit, there are two "spare"
> pairs there already. Why not use those?

True for 10Base-T or 100Base-TX, but Gigabit Ethernet uses all four
pairs.

> Otherwise, why not just another run of Cat-5? Unlike the telephone 
> 4-wire, the pairs are twisted, which will help to keep interference both
> in, and out.


-- 
David Empson
dempson@actrix.gen.nz
0
dempson
11/11/2015 10:51:04 AM
On 11/10/15 2:43 p, M. John Matlaw wrote:
> I've just run over a hundred feet of Cat-5e cable with no problem.  I
> believe it's unshielded (
> http://www.insigniaproducts.com/products/computer-speakers-accessories/NS-PNW5525.html
> ).
>
> I'd also like to run the same length of 4 conductor flat (modular?)
> cable (phone extension) along the same path and the simplest way would
> be right on top of the Cat-5e run.  But I'm thinking I might get cross
> interference if I do.  Is that right? If so, what should be the distance
> between the two lines.

A couple of questions:

1. What kind of electronic signals are you planning on sending over the 
4 conductor flat phone line? If it's just plain telephone audio 
(<10KHz), then there probably won't be any interference since the 
frequency of the twisted pair Ethernet is in the MHz range. Of course, 
the non-twisted phone line will be a giant antenna for any EMF; but if 
the phone circuit isn't connected to the Ethernet circuit(s), it 
shouldn't matter.

2. While it's more costly, have you considered running CAT-6 cable for 
future-proofing, especially if the physical installation is going to be 
difficult? It can handle _10_Gb Ethernet.
<http://serverfault.com/questions/438907/what-is-the-clock-frequency-inside-10gb-and-100gb-ethernet-cards> 
(see 10GbE side note)

-- 
Nous sommes Paris!

0
Fred
11/16/2015 9:02:46 PM
On 11/16/15 4:02 PM, Fred Moore wrote:
> On 11/10/15 2:43 p, M. John Matlaw wrote:
>> I've just run over a hundred feet of Cat-5e cable with no problem.  I
>> believe it's unshielded (
>> http://www.insigniaproducts.com/products/computer-speakers-accessories/NS-PNW5525.html
>>
>> ).
>>
>> I'd also like to run the same length of 4 conductor flat (modular?)
>> cable (phone extension) along the same path and the simplest way would
>> be right on top of the Cat-5e run.  But I'm thinking I might get cross
>> interference if I do.  Is that right? If so, what should be the distance
>> between the two lines.
>
> A couple of questions:
>
> 1. What kind of electronic signals are you planning on sending over the
> 4 conductor flat phone line? If it's just plain telephone audio
> (<10KHz), then there probably won't be any interference since the
> frequency of the twisted pair Ethernet is in the MHz range. Of course,
> the non-twisted phone line will be a giant antenna for any EMF; but if
> the phone circuit isn't connected to the Ethernet circuit(s), it
> shouldn't matter.
>
> 2. While it's more costly, have you considered running CAT-6 cable for
> future-proofing, especially if the physical installation is going to be
> difficult? It can handle _10_Gb Ethernet.
> <http://serverfault.com/questions/438907/what-is-the-clock-frequency-inside-10gb-and-100gb-ethernet-cards>
> (see 10GbE side note)
>
Thanks for this.  The 4 conductor is indeed for plain old telephone 
audio so I guess I'll give it a try laying it over the Ethernet cable.

I guess I should read up on this stuff but, sadly, my basic science is 
lacking.  The Time Warner internet I'm getting is supposed to be up to 
100/10 Mbps.
0
M
11/17/2015 12:42:17 PM
On 11/17/15 7:42 a, M. John Matlaw wrote:
> The Time Warner internet I'm getting is supposed to be up to 100/10 Mbps.

Certainly CAT-6 won't help in the cable modem to router link; but if you 
are going to be transferring files between computers using this cable or 
having several computers talking to each other at once over the cable, 
it can speed that up a bit if the computers have 1GBE or 10GBE.

-- 
Nous sommes Paris!

0
Fred
11/17/2015 8:25:47 PM
Reply: