Does two-way communication failure include one-way communication failure? Code 7600 means lost communication, more specifically two-way communication failure. I wonder whether two-way communication failure means losing the capability of maintaining two-way communication or  not? If the pilot can only hear but not transmit, is it also included in two-way communication failure?
7600 means a loss of two way communications, it's a way of letting ATC know you have a problem sending or receiving, or both.