Hi All

I received my 990/7700/LMF/SMS equipment last week and got everything hooked up. It sounded great, but I had a hum coming through my speakers. I read the directions to the 7700 related to ground loops. I unhooked the cable box and the hum went away. The instructions suggest calling the cable company and have them insert a ground loop isolator. I know almost nothing about electricity. So that I don't sound like an idiot on the telephone, can anyone describe to me what I should be asking for from the cable company?