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:
- Do not run the phone line on the same cable as Ethernet.
- 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.
OK, this is kind of a rambling question with a lot of details, but let me give you some leads on some of them:
Wall Plate
If you want to install a wall plate, you'll want to clean up the opening and then install a "low voltage mounting bracket", which is a square piece of plastic that frames the opening and provides a place to attach the plate:
(Wall plates come in sizes like 1-gang, 2-gang, etc., which indicates how many toggle switches or receptacles it can fit. You might want a 2-gang for that size opening and number of cables).
Then you can get a "keystone plate", which is a wall plate with small square holes in it (available in various widths and with different number of keystone holes). Here's a 1-gang, 2-keystone plate:
Finally, you get different keystone modules for the different types of cables. They snap into the holes in the plate. This lets you mix and match different connection types on the same plate. I'm not really sure what you mean by "tv type" and "telephone type", but here's a coax keystone module:
(EDIT: resist the temptation to skip the bracket and screw the plate directly to the wall. The screws will pull out of the drywall in about 2 seconds. I've seen this happen in several houses where people added coax wall plates or something, and didn't bother to do it right.)
Shelf & Mounting
As for wall-mounting options, it depends on how tidy you want to be. You could either mount a small shelf to the wall and place the electronics on that, or use your pegboard and find a way to strap the items to it.
Personally I would mount the shelf or pegboard just below the wiring plate, not on top of it. That would make it easier to mount the wall plate, and easier to make changes in the future.
Whatever you mount to the wall, make sure you attach it to the studs behind, not just screwing into the drywall.
Best Answer
Phone lines only use a single pair. As long as the same wire goes to the same pin on both ends of the RJ11 connector, it will work. Standard pair colors are black/yellow and red/green. A single line uses the two middle pins of the RJ11 connector, but two-line phones will use the inner and outer pairs.
T568A/B only applies to Ethernet connections.