DComTalk.com

Hello everyone!

Have a spec with keyed RJ45s called for. You know, reasoning that people
should not be able to plug a keyed data cord into a phone outlet and fry
their NIC. Probably made sense 10 years ago, but with a free NIC that you
normally get these days and central pins shortened to the ground anyways,
makes not sense to me. Pain in the neck to deal with, and the price is too
high, but the architect insists.

Can anyone post any real-world feedback on using those? I have never had
to actually use keyed cords, and I'm preparing an RFI with some data about
exactly how much it is a PITA to have keyed jacks/cords. Just need couple
juicy examples.

Anyone?

--
Dmitri Abaimov, RCDD
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I haven't even seen a keyed RJ in about 6 years!

I don't know of any NICs currently being manufactured that use a keyed
plug, they kinda died before Compaq bought DEC. One ploy you may try
would be to hand the architect a keyed patch cord and tell him to plug
it into their computer. That might be the best example.

In article <KT2Td.3184242$f47.570577@news.easynews.com>,
Dmitri(Cabling-Design.com) <info_at_cabling-design_dot_com@foo.com> wrote:

Hello everyone!

Have a spec with keyed RJ45s called for. You know, reasoning that people
should not be able to plug a keyed data cord into a phone outlet and fry
their NIC. Probably made sense 10 years ago, but with a free NIC that you
normally get these days and central pins shortened to the ground anyways,
makes not sense to me. Pain in the neck to deal with, and the price is too
high, but the architect insists.

Can anyone post any real-world feedback on using those? I have never had
to actually use keyed cords, and I'm preparing an RFI with some data about
exactly how much it is a PITA to have keyed jacks/cords. Just need couple
juicy examples.

Anyone?

--
Dmitri Abaimov, RCDD

Isn't an ethernet NIC transformer-coupled and really hard to fry ?

OTOH, lots of new PCs have the NIC on the mobo and it it does
the mobo is effectivly dead.

The lifetime cost of custom-spec cable plant might excees the cost
of any damaged equipment.

--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.

Al Dykes <adykes@panix.com> wrote:

Isn't an ethernet NIC transformer-coupled and really hard to fry ?

Yes, and somewhat. There is an isolation transformer required
to read the differential signals.

The "hard to fry" is relative. Ethernet survives hotplugging
extremely well. But is still very vulnerable to surges
(lightening induced ground differentials). I've seen more
dead hub/switch ports than ethernet cards.

-- Robert

"Justin Time" <a_user2000@yahoo.com> wrote in message
news:1109256457.221056.98250@z14g2000cwz.googlegroups.com...

I haven't even seen a keyed RJ in about 6 years!

I don't know of any NICs currently being manufactured that use a keyed
plug, they kinda died before Compaq bought DEC. One ploy you may try
would be to hand the architect a keyed patch cord and tell him to plug
it into their computer. That might be the best example.

Or point out to them that if they have to buy special patch cords with
regular on one end and keyed on the other, it will cost a whole lot
more, not to mention that the users will have to figure out which end
goes where. :-/

"Al Dykes" <adykes@panix.com> wrote in message
news:cvkpnc$4d7$1@panix5.panix.com...

In article <KT2Td.3184242$f47.570577@news.easynews.com>,
Dmitri(Cabling-Design.com) <info_at_cabling-design_dot_com@foo.com
wrote:
Hello everyone!

Have a spec with keyed RJ45s called for. You know, reasoning that
people
should not be able to plug a keyed data cord into a phone outlet and
fry
their NIC. Probably made sense 10 years ago, but with a free NIC that
you
normally get these days and central pins shortened to the ground
anyways,
makes not sense to me. Pain in the neck to deal with, and the price
is too
high, but the architect insists.

Can anyone post any real-world feedback on using those? I have never
had
to actually use keyed cords, and I'm preparing an RFI with some data
about
exactly how much it is a PITA to have keyed jacks/cords. Just need
couple
juicy examples.

Anyone?

--
Dmitri Abaimov, RCDD


Isn't an ethernet NIC transformer-coupled and really hard to fry ?

OTOH, lots of new PCs have the NIC on the mobo and it it does
the mobo is effectivly dead.

Well, if you fry a NIC on the mobo, then assuming nothing else happened,
you just pur a NIC in the slot and turn off the mobo NIC in the BIOS.
Of course some lusers haven't the ability to even insert a NIC into a PC
slot..

The lifetime cost of custom-spec cable plant might excees the cost
of any damaged equipment.

Good point. One other thought. The keyed jack is on the wall plate.
But is the patch panel also keyed? Seems to me that it doesn't have to
be, so no problem with the switches. Anyhow, I can't remember ever
seeing a keyed jack or plug, altho I did get a crimp tool with the keyed
hole in it.

On our last job, the contractor put in RJ-45 connectors for the phone
jacks. The scary part is that our digital PBX puts out 54VDC at about
150 mA, which makes for a nasty spark if it gets shorted by the
punchdown tool. I haven't heard of any problems yet, tho and it's been
two months..

--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.

Watson A.Name - "Watt Sun, the Dark Remover" wrote:

(snip regarding keyed RJ45 jacks)

Or point out to them that if they have to buy special patch cords with
regular on one end and keyed on the other, it will cost a whole lot
more, not to mention that the users will have to figure out which end
goes where. :-/

One place I used to do work with had keyed jacks, and supplied patch
cords with keyed plugs on one end. For direct connect that was fine,
but in some cases we needed a hub, which the university also supplied.

We then had to remove the key with a knife so that the plug would
work with the hub. It isn't so hard to do. I believe the jacks are
the same price.

-- glen