A completely disconnected computer can transmit data without any kind of transmitter
Phi Beta Iota: This requires installation of a program on the computer and ignores the generally existing electrical power path in and out of every computer that the Chinese (and Best Buy) have been using for over a decade. Every electrical connection is an ethernet connection. The number of CIOs that do not know this is quite startling. Many of us have been calling for data at rest encryption (without the infantile back doors from NSA and its complicit CEOs) in part because of the realization that all data is “visible” at one point or another.