RJ45 Varieties

RJ45 Varieties

Post by Ralponso Ursu » Tue, 27 May 2003 19:00:59



Does anyone here know any good technical reason not to use an RJ45 socket
intended for ISDN for CAT5 ethernet instead?  My local hardware store has a
wider variety of ISDN sockets than CAT5s and I'm tempted to try 'em.

--
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

 
 
 

RJ45 Varieties

Post by Stuart Robins » Tue, 27 May 2003 19:43:00


Quote:> Does anyone here know any good technical reason not to use an RJ45
> socket intended for ISDN for CAT5 ethernet instead?

Yes, it might not work.  

If you have a Cat5 tester, you could try one and see how it compares to a
proper Cat5 socket.

Otherwise stick to Cat5 sockets if you ant to be sure it will work.

Stuart.

 
 
 

RJ45 Varieties

Post by Ralponso Ursu » Tue, 27 May 2003 21:13:43


On Mon, 26 May 2003 11:43 +0100 (BST), Stuart Robinson


>> Does anyone here know any good technical reason not to use an RJ45
>> socket intended for ISDN for CAT5 ethernet instead?

> Yes, it might not work.

:-)  Well, that's more a result than a reason for the result.

The hardware store have an nice ISDN RJ45 plus analogue telephone combo-
socket (the sub-sockets can be isolated from each other natch) that would
save me knocking another hole in the wall at home.  (Especially since I've
already fed the CAT5 cable though the phone ducts).

Quote:> If you have a Cat5 tester, you could try one and see how it compares to a
> proper Cat5 socket.

Well, I guess the home LAN is going to be my CAT5 tester, because I'm going
to have to try it.  What's the worst that could happen?

Regards, Ralph.

--
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

 
 
 

RJ45 Varieties

Post by Tom Schmid » Tue, 27 May 2003 22:30:15



> On Mon, 26 May 2003 11:43 +0100 (BST), Stuart Robinson

> >> Does anyone here know any good technical reason not to use an RJ45
> >> socket intended for ISDN for CAT5 ethernet instead?

> > Yes, it might not work.

> :-)  Well, that's more a result than a reason for the result.

> The hardware store have an nice ISDN RJ45 plus analogue telephone combo-
> socket (the sub-sockets can be isolated from each other natch) that would
> save me knocking another hole in the wall at home.  (Especially since I've
> already fed the CAT5 cable though the phone ducts).

> > If you have a Cat5 tester, you could try one and see how it compares to
a
> > proper Cat5 socket.

> Well, I guess the home LAN is going to be my CAT5 tester, because I'm
going
> to have to try it.  What's the worst that could happen?

> Regards, Ralph.

> --
> Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

I'd strongly discourage you from taking this route. There an many sources of
and 8-position modular jacks designed for LAN use.

The worst that can happen is it wont work at all. Most likely your LAN will
not work at 100 Mbps (Fast Ethernet) but only at 10 (Ethernet), and it will
radiate and be susceptible to interference. Sending high-speed data over
copper twisted pair is an exacting task. If existing jacks were up to the
task TIA would have used them when they wrote the spec.

/Tom

 
 
 

RJ45 Varieties

Post by Ralponso Ursu » Tue, 27 May 2003 23:08:57






>> On Mon, 26 May 2003 11:43 +0100 (BST), Stuart Robinson

>> >> Does anyone here know any good technical reason not to use an RJ45
>> >> socket intended for ISDN for CAT5 ethernet instead?

>> > Yes, it might not work.

>> :-)  Well, that's more a result than a reason for the result.

>> The hardware store have an nice ISDN RJ45 plus analogue telephone combo-
>> socket (the sub-sockets can be isolated from each other natch) that
>> would
>> save me knocking another hole in the wall at home.  (Especially since
>> I've
>> already fed the CAT5 cable though the phone ducts).

>> > If you have a Cat5 tester, you could try one and see how it compares
>> to
> a
>> > proper Cat5 socket.

>> Well, I guess the home LAN is going to be my CAT5 tester, because I'm
> going
>> to have to try it.  What's the worst that could happen?

>> Regards, Ralph.

>> --
>> Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

> I'd strongly discourage you from taking this route. There an many sources
> of
> and 8-position modular jacks designed for LAN use.

If you can point me at a supplier of a combined CAT5 ethernet RJ45 and
Swiss T+T83 socket then I'd love to hear about it.

Quote:> The worst that can happen is it wont work at all. Most likely your LAN
> will
> not work at 100 Mbps (Fast Ethernet) but only at 10 (Ethernet), and it
> will
> radiate and be susceptible to interference. Sending high-speed data over
> copper twisted pair is an exacting task. If existing jacks were up to the
> task TIA would have used them when they wrote the spec.

Hmm, ISDN was specified in 1984 for 256KB/s, Cat5 in 1995 for 100MB/s ...
maybe you do have a point.  Damn it.

Regards, Ralph.

--
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

 
 
 

RJ45 Varieties

Post by J. Clark » Tue, 27 May 2003 23:12:40


On Mon, 26 May 2003 13:30:15 GMT




> > On Mon, 26 May 2003 11:43 +0100 (BST), Stuart Robinson

> > >> Does anyone here know any good technical reason not to use an RJ45
> > >> socket intended for ISDN for CAT5 ethernet instead?

> > > Yes, it might not work.

> > :-)  Well, that's more a result than a reason for the result.

> > The hardware store have an nice ISDN RJ45 plus analogue telephone combo-
> > socket (the sub-sockets can be isolated from each other natch) that would
> > save me knocking another hole in the wall at home.  (Especially since I've
> > already fed the CAT5 cable though the phone ducts).

> > > If you have a Cat5 tester, you could try one and see how it compares to
> a
> > > proper Cat5 socket.

> > Well, I guess the home LAN is going to be my CAT5 tester, because I'm
> going
> > to have to try it.  What's the worst that could happen?

> > Regards, Ralph.

> > --
> > Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

> I'd strongly discourage you from taking this route. There an many sources of
> and 8-position modular jacks designed for LAN use.

> The worst that can happen is it wont work at all. Most likely your LAN will
> not work at 100 Mbps (Fast Ethernet) but only at 10 (Ethernet), and it will
> radiate and be susceptible to interference. Sending high-speed data over
> copper twisted pair is an exacting task. If existing jacks were up to the
> task TIA would have used them when they wrote the spec.

The right way to do this is to use a two-hole wall plate with RJ-11 and RJ-48
keystone jacks.  Don't know where the OP is located, but in the US these are
available from any of the major home improvement chains.

Quote:> /Tom

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

RJ45 Varieties

Post by Tom Schmid » Wed, 28 May 2003 00:15:26





> Hmm, ISDN was specified in 1984 for 256KB/s, Cat5 in 1995 for 100MB/s ...
> maybe you do have a point.  Damn it.

> Regards, Ralph.

> --

Sorry I'm on the wrong side of the pond to have much experience.

This must be a common problem. There should be a solution that integrates
telephone and LAN wiring.

/Tom

 
 
 

RJ45 Varieties

Post by Stuart Robins » Wed, 28 May 2003 01:05:00


Quote:>  What's the worst that could happen?

The network will be unreliable, and you wont be sure know whats causing
it.

Better that it dont work at all.  

Stuart.

 
 
 

RJ45 Varieties

Post by Glen Herrmannsfeld » Wed, 28 May 2003 03:57:43



> Does anyone here know any good technical reason not to use an RJ45
> socket intended for ISDN for CAT5 ethernet instead?

Most likely it would work fine.  For home use, I don't see trying to follow
the standards as closesly as for business use.  In commercial settings, many
people will have to work on it, belieiving that others did it right.   For
home, it is just you, and you know how you built it.

Also, in home use the cable length is usually much shorter, which helps a
lot.

There is a pretty good chance it will be fine for everything below gigabit.
If you can afford gigabit, you can afford more expensive jacks.

Cat 5 jacks have better impedance matching characteristics, which are much
more important for gigabit.   Try to minimize the untwist length, too.

-- glen

 
 
 

RJ45 Varieties

Post by Robert Redelmeie » Wed, 28 May 2003 05:22:04



> Does anyone here know any good technical reason not to use an RJ45 socket
> intended for ISDN for CAT5 ethernet instead?  My local hardware store has a
> wider variety of ISDN sockets than CAT5s and I'm tempted to try 'em.

I wound not do this.  There are many kinds of 8p8c jacks.
Cat0 with*terminals, Cat3 with direct in-order punchdowns
and Cat5 with crosstalk limiting out-of-order punchdowns and
color codes.  Better performace from higher Categories.

The lower performance jacks might work, especially if the runs
are short.  But why take the chance for $1/jack?  Personally,
I like the color codes.  Locally, lower Cat parts are getting
harder to find, and Cat5 has come down in price and are
available in more colors.

-- Robert in Houston

 
 
 

RJ45 Varieties

Post by D. Abaimo » Thu, 29 May 2003 02:12:03


ISDN-rated jacks are not rated for CAT5 (or CAT5E to that matter). They have
8 conductors, true, but they are intended for much lower signal frequencies.

--
Dmitri Abaimov
http://www.cabling-design.com
Residential Cabling Guide and other useful online resources for premises
wiring users and professionals
http://www.cabling-design.com/resources/documents/residential.html
Residential Cabling Guide 2003

Quote:> Does anyone here know any good technical reason not to use an RJ45 socket
> intended for ISDN for CAT5 ethernet instead?  My local hardware store has
a
> wider variety of ISDN sockets than CAT5s and I'm tempted to try 'em.

> --
> Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

 
 
 

1. Is RJ45 With Notch Same as RJ45 Without Notch?

The Subject says it all.

I would like to ensure that these RJ45 wall jacks with a notch will
work.  (I am pretty sure that they are Digital Equipment Corp. (DEC)
RJ45 wall jacks that have been installed in some new offices.)  Will
these work with the standard RJ45 (without notch) plugs?

Thanks,

Phill

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