My Panasonic phone mod no. KX-TG7871 rings but after answering I can hear the caller but the caller is unable to hear me. Yesterday it was the opposite till I read the trouble shoot page and reset the code to tone. I need to hear the caller and visa versa at the same time. Yesterday before resetting anything, I unplugged the cord from the receptacle and after plugging it back the phone was good again. Now it seems that I must keep unplugging and plugging it back to get it working.