downlink clarification

[currydem]

"You'll want to do this in your setup() function and then define a void (callback)(const byte payload, size_t length, int rssi) function somewhere else in your sketch." for the downlink messages I'm not sure what this means. currently when I send down single byte downlink messages all I get is "49" no matter what I send.

[markhellmanns]

see issue #25