A system apparatus and method for providing access security for a subject device. The apparatus includes a security check unit (SCU) configured to be coupled to a transmission medium. The SCU is configured to monitor signals on the transmission medium and to detect an attempt by a first device coupled to the transmission medium to access a second device coupled to the transmission medium based upon the signals. The SCU is also configured to determine an identity of the first device based upon the signals and to control access to the second device by the first device dependent upon the identity of the first device. The method includes monitoring signals and detecting an attempt by an additional device to access the subject device based upon the signals. The method also includes using the signals to determine an identity of the additional device and controlling access to the subject device dependent upon the identity of the additional device.