Note1: RS-232: RXD, TXD, GND
               Signal lines are RXD, TXD and GND
               Program download port

Note2: RS RS-232: RXD, TXD, CTS, RTS, GND
             or RS-485: Data+, Data-; Self-tuner inside

Note3: RS-232: RXD, TXD, CTS, RTS, DSR, DTR, DCD, RI, GND