I have been using the KQ-330 module with great success after a lot of running in circle due to the very limited English Litterature.
KQ-330 is the PLC Modem plus MCU and KQ-130 is the board with al the coupling and filtering component to hook directly to power lines.
Module is taking care of all the encoding and modulation.
Only thing that you have to be careful with is the way you build up your frames since you want to work on with the MODE pin tied down to let the module do all the filtering out.
Frame are :
1 st BYTE : Number of Bytes in the message
Other BYTES : Data
and you receive :
1st BYTE : Nbr of byte in the packet followed by the message.
Xmit and receive buffer is roughly 250 bytes.
One thing to keep in mind is that it is very slow so make sure that you have enough delays between your packets.
One thing I would like to know is the actual distance one can reach, I have read anything from a couple hunderd meters to 1.5 km ???