I have tried this with a Panasonic phone and with a 3rd party branded phone that has a compatible adapter. For sound, I can hear, but it is muffled. When I tried speaking, it kept cutting out, and I had to go back to the handset.I find it unlikely that this is a Panasonic-branded headset. There is nothing printed on it indicating a part number, no instructions (though probably not necessary,) etc. However, this is no surprise for the price.