Abstract: An apparatus and method for detecting a connection to a data transmission network functions by detecting the network signal energy on a network cable while avoiding the problems of excessive power consumption and generation of excessive electrical noise. By monitoring the receive network lines and determining if there is electrical energy on the cable in the form particular to the type of network supported by the network adaptor card, the host computing device can power-down the transceiver associated with the network adaptor card until an active network connection is detected.