A signal transmission system includes a controller interface, a protocol engine to convert data based on at least one protocol, and a common protocol interface coupled between the controller interface and the protocol engine. The controller interface includes or is coupled to a common dispatcher, and the data is to be transmitted between the controller interface and protocol engine through the common protocol interface and common dispatcher. The same protocol engine may convert data into different protocols, with all of the converted data be transmitted to or received from the controller interface through the common dispatcher and common protocol interface.