I like the idea of the OF option. To me there are two options that make sense. Data only, and packet format. In the XBee world it is a different firmware package if you want packeted data or a stream. Either everything is encoded in a packetized format, or it is a byte stream to the configured destination. Different applications demand separate behaviors, but tend to be one or the other. For a simple sensor I normally want stream mode, send these bytes now. The listener is either a paired node, and wants a stream or a collection point in a multi-drop, many to 1, config, and always wants the address, and RSSI etc. OF works for me, but I would not implement more than the two options unless these is a use case I missed. (Once I have to unwrap data, all I care is that I can unambiguously do it. (byte counts, no parsing please!))