RJ45 splitter for Ethernet - possible ?

I turned off the DST bit, see if that helps

The time indicated for your post (in the date column) says 9:08 PM, which is offset an hour from the time you have indicated below (2007 hrs., i.e.: 8:07 PM).

Best Regards, News Reader

snipped-for-privacy@aol.com wrote:

The time indicated for your post (in the date column) says 9:09 PM, still an hour ahead.

Best Regards, News Reader

snipped-for-privacy@aol.com wrote:

No, it's not recommended (which I probably should have mentioned), but it was designed to work.

-Larry Jones

It's going to be a long year. -- Calvin

Absolutely.

The former is true, the latter is debatable. Cat5 cable is used for phone wiring, so the voltage is not a problem for it (in fact, most Cat5 cable is rated for 300V). The IEEE 802.3 spec for twisted pair ethernet requires devices to provide at least 1500V of isolation, so it's not a problem for the attached devices, either. And the baseband signal is up in the MHz range, so the receiver won't even see a 20Hz signal. Like I said, twisted pair ethernet was specifically designed to coexist with ordinary phone circuits in the same cable, although that's not recommended for structured wiring systems.

-Larry Jones

No one can prove I did that!! -- Calvin

I suspect that both are true.

I'm sure it's some kind of legitimate product, but there aren't enough details in the descriptions to know what the legitimate uses are!

There are lots of them by a variety of sellers, although the pictures and descriptions (in somewhat fractured English) are very similar. Here are a couple of examples:

-Larry Jones

I've got PLENTY of common sense! I just choose to ignore it. -- Calvin

I'm baffled, I only know of one clock, the one in the lower right of the screen. I don't know why it shows up as 909 in the header

Agent said 809 on the title bar when I looked at it

True

False - We have several 200 foot runs of buried CAT5 that carry

The point is not whether the "cable" can withstand high voltage.

The point is that Ethernet is a low voltage, low current implementation.

The issue is induction, and induction results from current, not voltage.

If you think a high current, low frequency signal cannot impact the receiver, you are incorrect.

If you were correct, we would not observe the minimum separation distances from EMI sources that we do, when installing network cabling.

We keep data cabling away from AC wiring (i.e.: 60 Hz), and if we have to cross paths with AC, we ensure that we are perpendicular to the AC wiring, and never parallel to it, due to the effects of induction.

Best Regards, News Reader

snipped-for-privacy@siemens.com wrote:

Pretty sad when the seller can't provide enough detail (pin outs) for you to determine what it is you are buying.

I provided a link in one of my earlier posts for a product that exists from a reputable company (Hubbell).

Best Regards, News Reader

snipped-for-privacy@siemens.com wrote:

In comp.dcom.cabling News Reader wrote in part:

Well, technically ULF is seen at the receiver, but it is too slow and neutralized by balanced signalling to make any difference in the detection process.

There are many other reasons for separation. First and foremost is the dreaded electrical inspector who will often insist upon it (for electrical "safety") and her word is law. Second, some AC loads get very HF noisy (arc welders, certain motors and X-ray machines are frequently cited) and inject high freq noise onto AC. This noise can be troublesome.

A clean AC draw (incandescent lighting) may produce some 60 Hz induction, but it is harmless and easily rejected by the receiver. Similarly the telephone ring 88V, 20Hz, unless you have an antique phone with contacts on the bell armature. Even then the protocols are robust and will retransmit.

Please refrain from top-posting. The convention is quote-and-respond which makes following threads and side-comments easier.

-- Robert

I'll yield to your superior knowledge of the subject matter, and adjust my top-posting behavior.

Best Regards, News Reader

(snip)

V=L di/dt. It depends on current and frequency. Low di/dt also results in low inductive coupling.

I believe ethernet can work with common mode 240VAC on the line. (Be careful around it, though.) I was going to test it someday but still haven't done it.

Differential signaling is pretty good at keeping the signals apart. Except for the case of arc welders (mentioned here in the past) it is rarely a problem.

-- glen

So is POTS, save for ringing.

Yes, and ringing is low current (about 50mA, max). When it's on Cat5 cable, it's on a twisted pair as is the ethernet signal and the twists are different, which almost completely eliminates any inductive coupling. What little is left is almost entirely common mode, which the balanced ethernet receiver is almost entirely immune to anyway.

Have you never heard of a low-pass filter?

There are a number of reasons for that advice, but the 60Hz AC is not one of them. The noise concern is for switching transients from things like motors and arc welders, which can easily generate noise in the MHz range which could interfere with the ethernet signal. Note, however, that AC wiring is *much* higher current than POTS ringing, and it's not on twisted pair cable. Nonetheless, Cat5 has incredibly noise rejection. People who have tried to provoke errors from induced noise have found it quite difficult to do.

-Larry Jones

You should see me when I lose in real life! -- Calvin

Which is precisely *why* twisted-pair ethernet was designed to coexist with those kinds of signals.

-Larry Jones

Monopoly is more fun when you make your own Chance cards. -- Calvin

Excellent response.

I stand corrected.

Best Regards, News Reader

That is my experience. I have been parroting the company line about florecent ballasts and ringing current, simply because it is accepted practice but I have never fixed a problem by moving a Cat5 away from these things. You just do it so somebody else doesn't come along and say "there is your problem", waste a lot of time and not fix anything either.