Systems and methods for operating transponders that automatically accommodate multiple received signal types. The different signal types may include different clients such as, e.g., SONET/SDH, G.709, 10 Gigabit Ethernet, etc. as well as different data rates. A transponder can automatically detect the client signal type and data rate and respond by processing the received signal appropriately, notifying a control processor, and invoking an appropriate performance monitoring method. This maximizes the network operator's flexibility and ease of configuration.