A system comprising: a control device (108, 112, 116, 120, 124, 138, 142, 146, 150, 154, 180) for controlling an amount of power provided to an electrical load, wherein the control device is one of a control-source device or a control-target device included in a plurality of control devices, the control device comprising: a wireless communication circuit (1602, 1708) configured to send and receive digital messages; and a control circuit (1604, 1702) communicatively coupled to the wireless communication circuit, the control circuit configured to: receive a broadcast discovery message transmitted by a load control discovery device; determine a received signal strength (RSSI) at which the broadcast discovery message is received; determine that the received signal strength is above a predetermined signal strength threshold; and when the signal strength at which the broadcast discovery message is received is above the predetermined signal strength threshold, send, via the wireless communication circuit, a response message, wherein the response message is configured to report receipt of the broadcast discovery message, and wherein the response message includes a device identifier of the control device and the received signal strength (RSSI) of the broadcast discovery message; characterised in that said control circuit is configured to perform above steps responsive to receipt of a discovery trigger message from a system controller and subsequent entry of the control device into a discovery mode. a wireless communication circuit (1602, 1708) configured to send and receive digital messages; and a control circuit (1604, 1702) communicatively coupled to the wireless communication circuit, the control circuit configured to: receive a broadcast discovery message transmitted by a load control discovery device; determine a received signal strength (RSSI) at which the broadcast discovery message is received; determine that the received signal strength is above a predetermined signal strength threshold; and when the signal strength at which the broadcast discovery message is received is above the predetermined signal strength threshold, send, via the wireless communication circuit, a response message, wherein the response message is configured to report receipt of the broadcast discovery message, and wherein the response message includes a device identifier of the control device and the received signal strength (RSSI) of the broadcast discovery message; characterised in that said control circuit is configured to perform above steps responsive to receipt of a discovery trigger message from a system controller and subsequent entry of the control device into a discovery mode. receive a broadcast discovery message transmitted by a load control discovery device; determine a received signal strength (RSSI) at which the broadcast discovery message is received; determine that the received signal strength is above a predetermined signal strength threshold; and when the signal strength at which the broadcast discovery message is received is above the predetermined signal strength threshold, send, via the wireless communication circuit, a response message, wherein the response message is configured to report receipt of the broadcast discovery message, and wherein the response message includes a device identifier of the control device and the received signal strength (RSSI) of the broadcast discovery message; characterised in that said control circuit is configured to perform above steps responsive to receipt of a discovery trigger message from a system controller and subsequent entry of the control device into a discovery mode.