put metal tape around the plug, and wire that metal tape to an electrical outlet. Someone will try to unplug it once, and never again. Or, just do what I do. Take a plate without any holes in it, a cover plate that is used in homes sometimes, and fill an area out in the side just large enough for the line cord to fit through. Then, plug the line cord in to the keystone jack, and put the cover on, feeding the wire through that little notch you made on the side of it, then you will have to unscrew the plate to get the plug out of the jack. Up at the phone, just snip the tab off of the plug. And anyway, if ringing phones get on your nerves then why on earth are you working at a call center? Oh, and if this is a large call center and it sounds like alot of work to be filing notches out of 50 billion different plates, just use a 1 port wall plate, with a keystone jack, but dont actually "snap" the keystone into the plate, Glue it or Duct tape it to the back of the junction box. If that doesnt work, its time to break out the paddle, one with the little holes in it.