In some embodiments, a motor drive system includes a communication subassembly electrically coupled to a control subassembly for providing communication between the control subassembly and at least one external device. The control subassembly and the communication subassembly transmit and receive control data independently of messaging data, greatly enhancing performance and reducing the workload of processors on the control subassembly and communication subassembly. Additionally, the control subassembly and the communication subassembly transmit message data via sequence count based messaging. Communications between the communication subassembly and the control subassembly may include a series of timeout periods and retries, increasing reliability.