Along with type="powerline" attribute, the powerline configuration must provide a proto attribute of either "CM11A" or "PLM" to indicate the interface protocol, and a transport attribute of "direct" or "redir". If the thread specifies the direct transport, then the device should be specified in the "port" attribute, otherwise in the case of the redir transport, the "host" attribute should contain the hostname of the port redirector server and the "port" attribute contains the port on which the server is listening
<thread port="/dev/ttyUSB0" proto="PLM" transport="direct" type="powerline"/>