Wiring – problem with a media enclosure box in a laundry room

If you are running telephone and ethernet on the same cable then it is most likely interference from the telephone pair. POTS (Plain Old Telephone Sockets) have a constant voltage of 50V and ring at 75V with an engaged voltage of 35V.

It will not be the electrical 110V causing interference because your switch cancels the noise out because it if grounded(negative) to your home installation(on which your switch runs and knows about this frequency so it can eliminate is successfully).

Why will it pick up noise from the telephone voltage? Because the power is coming from outside your house on a separate ground loop that has a unique frequency resonance which is not the same as your houses' frequency(not talking about 50hz/60hz - But electromagnetic radiation). This will cause the switch to suffer packet loss because it cannot successfully XOR noise that is generated from the phone lines voltage frequency.

To solve this problem in order of cheapest to most expensive:

1. Do not run the phone line on the same cable as Ethernet.
2. Buy a VoiP router like Linksys SPA family and plug your phone line in there and route all traffic via ether to IP phones.(But also you can then run the phone out from the SPA because it is grounded at your home and you are within the loop)

Please Note:

Some distribution boxes have a lightning protector or surge protector installed that link in the actual earth(also called ground) but earth is used in UK, Some parts of EU and ZA(not sure about USA) to detect appliance fault and gives lightning a short path to the earth. Usually the earth bar is connected to a rod that goes into the ground outside the house or bound to the incoming phase shield which is earthed at the main power box. When I talk about ground I mean the actual negative(-) wire of an appliance or analog / digital circuit.

NEVER TRY TO GROUND(NEGATIVE) THE TELEPHONE TO YOUR HOME GROUND OR A GROUND LOOP ISOLATOR

As it seems the OP grounded his telephone but it is most likely earthing the cable not actual negative.

Doing this can cause damage to the telephone network costing you thousands dollars and/or cause death or serious bodily injury from electrical shock. Remember that the ground of your home has a different impedance than ground from the telephone network and can result in 110V electrical shock! That is why it is illegal to rewire telephone sockets in many countries. For your own safety.

I take it you're hoping to poke sticks of conduit up from the basement and hope to come out in the attic without hitting anything? It could happen, but I'd be rather surprised. 1.5" conduit is fairly chunky, I think you're likely to hit something. If you wanted to fish a few runs of Cat 6 I'd say your chances were good. But conduit? (BTW, bonus points for knowing better than trying to run inside the duct.)

Even if there's obstructions, it may be possible to make the run by cutting discrete access holes to cut out the obstructions, assuming they are non-structural. If you haven't yet done so, examine each floor carefully to determine if there's enough space to even make the run. Measure carefully to arrive at accurate void dimensions, and ensure the proposed run aligns on each floor, which may not be that simple. Once you've determined it's feasible, start pushing pipe, keeping track how much length is pushed up. You'll likely hit something. Figure out where it is vertically. Gain access and clear the obstruction. Repeat as necessary until the attic is reached. Good Luck!