ControlNet Taps?

Is it possible to use a BNC T-splitter rather than the ControlNet taps provided by AB? I know they have some passive devices built in but are they just for filtering or is there a different purpose? I would appreciate it if i could recieve a technical reason why not rather than just a no.

Thanks

Nothing guys???

I think the AB taps are just fancy versions of the standard equipment. They give you that nice trunk cable.

In our test setup, we haven't needed to follow the EXACT standard. We're not using terminators, and we've got two ends of the last tee connected to equipment...

Try it out, then you'll know!

The passive electronics inside a ControlNet tap aren't just for filtering, they're to reduce the connector-related reflections you get anytime you go through a bulkhead or tap with a RF-frequency signal.

The idea behind a ControlNet tap is to, well, "tap off" just a small amount of the signal on the trunk line and deliver it with maximum amplitude and clarity to the end of a 1-meter cable.

Part 2 of the ControlNet Specification includes a table of characteristic specifications that a ControlNet tap must meet for inductance, capacitance, resistance, and transmission and reflection characteristics.

If you were to cut one open, you'd find a 56 pF capacitor, a .56 uH inductor, and a little 18-turn autotransformer wound around a toroidal core all connected in parallel.

In my experience, you will NOT get good results using BNC tees in place of ControlNet taps. It might work for a small network or for a little while, but you're setting yourself up for a frustrating and fruitless experiment in pennywisdom. Removal of non-spec taps is part of every ControlNet troubleshooter's checklist.

Normal BNC 'T' connectors work fine for quick hookups and testing on the bench, but I would never deploy them in an actual installation.

Ken makes good points about the passive electronics within them, and the fact that if you call for support at all, ever, you will first be instructed to switch out BNC T connectors before they will go any further.

One point Ken forgot to mention, which is VITAL though, is that ControlNet is an UNGROUNDED network. At no point should the outer conductor touch ground, or you will have endless transmission problems. Since Normal T's are fully metallic, you would be hard-pressed to ensure that they never contact any grounded metal, and wrapping things in electrical tape just doesn't inspire confidence

One more problem, is that T connectors are notorious for wierd failures (remember Coax-Ethernet?).

Comm Hiway

Hi Savage,
This line is for communication. There are two types of devices for dividing the line. The Tap is for Accessing the trunk line, the "out" side has length limits and Attenuates the signal. The other two connectors are for the Trunk line,or main comm line labled In and Out. The Splitter is for adding a segment to the trunkline.
These devices are for impedance matching. They reduce SWR or reflections on the comm cable. On short runs with only one or two devices Ive seen people not use them.
They are important, Id use them

Bruce

As always Ken is absolutely correct, AB Tap is not just a TEE.
And as always something out of spec may work in the lab or even on the machine for a while. Don't take a chance. Price of tap is much less than labor for a few days of troubleshooting.
I would not mess with controlnet at all - get it right from start.
I was told by AB: 95% ControlNet problems are media related.

BTW, I saw recently new CNET setup which did not work:

[1756CNB] -> TRUNK LINE -> [ port A 1794ACNR Port B] -> TRUNK LINE -> [ port A 1794ACNR]

Guess what - fix was quick and easy and happy customer got his bill $$$$

Originally posted by Contr_Conn:

BTW, I saw recently new CNET setup which did not work:

Click to expand...

That's pretty good. I recently had an electrical designer where I work try to lay out a network like that. Just by dumb luck I had seen a CNET implementation before and knew that wouldn't work so well. We caught that one before anything was put together. It seems like kind of the natural thing to do though, doesn't it?

Keith

The darn cable was just a couple of inches too short...

Do you think it'd work?
[attachment]

grs said:

The darn cable was just a couple of inches too short...

Do you think it'd work?
[attachment]

Click to expand...

Nope, but I've seen that and worse after the installing electrician was finished "installing" our gear... Pulling all the new CAT5 was a real pain my the a$$.

Comm Cable

grs said:

The darn cable was just a couple of inches too short...

Do you think it'd work?
[attachment]

Click to expand...

No, not likely.............LOL....

This is like terminating DH+ on terminal strip, running a jumper to the processor. Seen It many times, gives nothing but trouble.

grs said:

The darn cable was just a couple of inches too short...

Do you think it'd work?
[attachment]

Click to expand...

OW O GW B BW G.... Yep, that kills me How about DH+ Tee'd on a terminal strip? then run the branch 100'.