For example, you will need a Sennheiser CCEL190-2 cable to connect to standard phone. Do an Internet search and you will find [...]the only American reseller to advertise this critical cable (plus they sell the CC550 for less). You will also need a CEDPC1 to connect to a PC and they have a long list of others for commercial phone systems. Otherwise, this is one of a kind. I'm not hearing impaired, but especially since phone companies no longer work to "hear a pin drop" in addition to handsets not fitting against the head and headsets focusing first on being light, I've desperately needed something better. This is it. It certainly costs more than any other headset, but that's nothing if you spend hours a day on the phone.