A communication protocol for a lighting control system having a plurality of control devices coupled to a communication link uses a polling technique to coordinate the transmission of digital messages between the control devices. When the control devices are powered up, one of the control devices is established as a “master” device. During normal operation, the master device transmits a standard poll message to each of the control devices in succession using a unique semi-permanent Poll ID for each of the control devices. The master device periodically transmits a Poll-ID-Request poll message to the control devices allow those devices that do not have a Poll ID to request a Poll ID. If a control device determines either that the master device is not transmitting poll messages to it, or that another control device has the same Poll ID, the control device drops its Poll ID and acquires another Poll ID.