Due to its modularity and scalability, modular multilevel converter is a promising topology for medium voltage applications, such as energy storage or motor drives. Because of the large number of modules, the wiring can become complex if the conventional star topology communication network is used. To solve this issue, a communication link that uses a ring topology to connect the central controller and the modules provides an efficient solution. The information exchanged on this link includes real time data, such as duty cycle, measurements and fault feedback. Thus, a dedicated high-speed communication protocol is needed. This paper reviews two possible protocols for modular multilevel converter communication, PES Net and SyCCo bus. After introducing the operating principles, their performance is compared and discussed. SyCCo bus is implemented using Altera Cyclone IV FPGA. Tests are conducted to analyze the communication delay of SyCCo bus. The implementation is made open source.