<p>One switch-state aggregation technique uses a digital-to-analog converter in combination with an analog-to-digital converter to aggregate the state of a plurality of switches. Another switch-state aggregation technique uses input/output lines of a processor to aggregate the state of a plurality of switches and to communicate data other than the state of the switches. These techniques can be used to aggregate information about whether a plug or other connector is inserted into the ports of a patch panel or other telecommunication or communication assembly, system, or device.</p>