[plug] home cat5 issues

Phillip Bennett phillip at mve.com
Wed Mar 19 21:35:03 WST 2008


Just a thought, and I'm quite likely wrong here....

Could it be that it's wired wrong?  What I mean is that you've effectively 
made a cable from an RJ45 to a socket and then plugged something into it... 
Will the pinout be correct in this case?  If you make a cable, usually it's 
either RJ45 to RJ45 OR socket to socket (for use with patch cables).  Making 
a cable from an RJ45 to a socket, and THEN putting a patchlead on only one 
end confuses me (could have drawn the diagrams to confirm, but I'm too lazy 
and busy right now) Would it actually work?

As I say, it's just a thought and I'm probably wrong.  I just thought I'd 
put it out there.

Phil.

----- Original Message ----- 
From: "Gavin Chester" <gavin.chester at gmail.com>
To: "plug" <plug at plug.org.au>
Sent: Wednesday, March 19, 2008 8:09 AM
Subject: Re: [plug] home cat5 issues


> On Wed, 2008-03-19 at 16:10 +0900, Mark J Gaynor wrote:
>> I have not heard of a modified star topology, a star is a star. I would 
>> say
>> that you
>> have seriously changed the characteristics of the cable by placing 
>> sockets
>> along
>> its length. If the sockets were a normalized type (not come across cat5
>> normalized
>> sockets either) then I would say the idea would work. A normalized socket
>> breaks
>> the connection at the point of connection. I would say that stray 
>> capacity
>> is your
>> worse enemy here, resulting in a sad lack of speed.
>>
>> Mark
>
> I hadn't thought of stray capacitance from unused sockets :-/. I'd
> thought an unused socket without breaking the cable would equal simple
> stripped insulation :-/ That is, I was hoping that without physically
> breaking the connection when I interpose a keystone socket that it would
> be seen as one cable - potentially of varying length.
>
> Recall my previously discussed test cable of 30m with a keystone socket
> interposed halfway along its length with crimped connectors each end.
> Then I can elect to use it as a patch cable connected end to end - OR
> substitute the halfway socket leaving the rest of the cable flapping in
> the breeze. Sort of like quickly choosing between a 30m or 15m length of
> patch cable when it actually still the same cable. Without breaking
> continuity I thought this should work :-/. Another diagram would help,
> perhaps:
>
> SCENARIO 1/
>
> X---------------O---------------X
> | | |
> PC Router
>
> One cable using end crimp connectors - this WORKS.
>
> SCENARIO 2/
>
> X---------------O---------------X
> | | |
> PC Router
>
> One cable using end crimp connector to midway keystone
> - this does NOT work.
>
> Got me stumped. And, yes I've triple checked the integrity and pinouts
> of teh keystone - even temporarily changed it to T568B, instead of
> T568A, just for the hell of it :-/
>
> The next test I'm going to try to replicate my problem is to make a
> patch cable with a "Y" connection so that I choose either of B or C
> connected to A - not at same time, of course.
>
> Router
> A
> |
> |
> |
> |
> B------------------C
> |
> PC
>
> Gavin
>
>> --
>>
>> *********** REPLY SEPARATOR  ***********
>>
>> On 19/03/2008 at 3:15 PM Gavin Chester wrote:
>>
>> >On Wed, 2008-03-19 at 14:46 +0900, Hagar Horrible wrote:
>> >> On Wed, 19 Mar 2008, Gavin Chester wrote:
>> >-snip-
>> >
>> >> A simple diagram of my modified star
>> >> > topology may help:
>> >> >
>> >> > X-------O---------O------O------X
>> >> > | |
>> >> > | |
>> >> > PC Router
>> >> >
>> >> > where each 'O' is a keystone socket and 'X' is crimped cable 
>> >> > connector
>> >> > on a single cat5e cable placed loose on the floor. All connections 
>> >> > and
>> >> > sockets test as good, but only X-X works, any combination of X-O or
>> O-O
>> >> > fails. WHY? Any ideas welcome. BTW: I have used two brand of 
>> >> > keystone
>> >> > socket, in case that crossed your mind.
>> >
>> >> 1) Are you using only 1 cable per computer?
>> >
>> >Yes, I have laid five parallel cat5e cables - one for each
>> >PC/router/printer, but each cable is configured as above with multiple
>> >drop offs to different points/rooms. Each will only serve one appliance
>> >at a time - the extra drop-off points jsut give flexibility as to where
>> >the appliance is placed on the cable.
>> >>
>> >> 2) What was the pin/color combination for each plug?
>> >
>> >Done to T568A specs.
>> >
>> >> 3) was the cable single core ( for fixed wireing )
>> >> or twisted (core for more mobile solutions)?
>> >
>> >Single core cat5e
>> >
>> >> 4) is your router a hub or a switch and what
>> >> about the nic in the computers ?
>> >
>> >Important questions, but I don't think relevant to my issue which
>> >revolves around connecting to keystone sockets as opposed to crimp
>> >end-connectors. See other follow up post for info.
>> >
>> >gavin
>> >
>> >_______________________________________________
>> >PLUG discussion list: plug at plug.org.au
>> >http://www.plug.org.au/mailman/listinfo/plug
>> >Committee e-mail: committee at plug.linux.org.au
>>
>> *********** END REPLY MESSAGE  ***********
>>
>>
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>
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> http://www.plug.org.au/mailman/listinfo/plug
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> 




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