atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Tapping at the punchdown block for a recorder installation

We're a recording company that installs recorders at call centers.

In our standard "station-side" installation, we have our call center clients ask their wiring people to cross-connect to the punchdown block and terminate to one or more amphenol cables that then plug into the recording interface boards on our PC-based recorders.

In a recent NEC installation, when the client had the wiring installed, their phones stopped working. The manufacturer of the recording boards we use tell us that the cross-connects have to be connected to something; if they don't it causes "reflection".

My problem with this situation (assuming I understand it correctly) is that if the recorder needs to be repaired, the phones will stop working unless the phone guy comes back and disconnects the cross-connects.

Any solutions to this problem?

We want to help, but you will get more questions here than answers, unless we can get more info.

We have spoken before, I believe, about a similar situation. Please see my remarks, and those of other forum members, in the referenced thread, from May of this year. At that time, we recommended that you avail yourself of the services of a professional installer. Personally, I would say that that advice still stands.

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What is the name and model number of the recording equipment? What wiring scheme is recommended by the manufacturer? Do you see the letters "RJ" followed by other letters or numbers on the installation instructions where it talks about interconnecting to a phone system?

If you are the company who installs the equipment, why aren't you familiar with the way the wiring impacts on the customer's equipment? Are the "wiring people" (whatever that means) licensed electricians with specialized telecommunications training?

What does the customer (or what do you) ask the "WP" to do? Are they installing some sort of wiring or jacks that inserts a series connection between the phones and your equipment?

You first ask about a brand-new installation where the phones stopped working. When that happened, did the "WP" stop what they were doing and analyze and correct the problem? If, one minute, phones are working, and then, right after someone meddles with the wiring, all the phones stop working, I would be concerned that the "WP" might not know what they're doing, or to be charitable, perhaps they have not been instructed properly as to the consequences of their actions.

Did the phones start working again? Who did what to get that to happen?

Then you ask about a scenario where you might be required to remove, at least electrically, your recorder, and wonder whether the phones will continue to work. Has that ever happened before? Does the manufacturer offer any advice or instructions that would guide you in that eventuality? Can you give us a hint as to what the instructions say? How many of these installations have you had done?

I have been working on phones for 45 years, and I have never heard of a term in telephony called "reflection." Please have your manufacturer explain what that means, and then relay the information to this forum.

If your company does not have the expertise to do these installations yourself, then my suggestion would be to hire a telecom professional to work for you directly, as a subcontractor, on these installations. They should fully acquaint themselves with the wiring requirements before meddling with a customer's equipment.

Oh...wait...that's what I said last time.

Arthur, I've heard of and suffered the results of reflection. Mitel SS ports in my case. The active jack AND the idle jack were both close to max on wiring length. Disconnecting the idle jack, without disturbing the cross-connect othe the active jack punch's, cleared up echo, flickering LED's, dropping calls, and distorted audio. Digital signals at a high enough speed, with the right wire (or would that be wrong) distance, can reflect 180 degrees out of phase with the signal, partially and intermittently cancelling the data stream to the SS. Think about microwave and the length of waveguides. Every 1/4 wavelength the condition (?) of the wave changes. Hmmm, too long ago, someone else feel free to jump in here. Besides, I gotta go, mom was trimming the bushes and trimmed the power cord, so it's off to Lowe's for a new female end. At least she only cut off about 2 feet on a 50 foot cord.
And since the cord wouldn't be fixed before dark, I'll get it tommorrow, when I take mom to work at wallyworld,2 blocks from Lowe's and save a gallon of gas! John C.

There's a lot of words in that sentence, and God bless you if you can decipher what all those non-sequitors mean. I understand reflection as it applies to RF propagation. If you have somehow managed to understand what's going on, after distilling the sequence of events that are being described, then please go right ahead and offer an explanation. I am at a loss.


What wiring? The original wiring? The recording equipment wiring? With the recording eq connected? Disconnected? Was the eq powered up? Did ALL the phones stop working? Are the lines at their maximum length, as you suggest in your example? The maximum length could be quite a large distance.

Well, duh...why install something that isn't cross-connected? Or is the implication that the eq was installed, and the cross-connections run, and then...what?...the amphenols were pulled? We still haven't heard what connection arrangement is recommended or being used. We are once again operating in a vaccuum, and making stabs in the dark.

Patient: I have a very bad pain.

Doctor: And where is this pain located?

Patient: I'll let you figure that out, you're the doctor.

This was also posted in the NEC forum.