A termination unit (144) for use with a system that permits the monitoring of a computer network to perform network inventories. The termination unit takes the form of a cap that engages the termination face of a network jack and has a sensing circuit (246) integrated therewith so that, once engaged with the jack, the sensing circuit is connected to two terminals of the jack. The sensing circuit may include a resistor, capacitor or inductor, any of which provide a known sensing value that is different than a sensed value of an end-user device used on the network, but less than infinity so that the system senses when an end-user device is connected to or disconnected from the network.