Updated Protocol and compatibility (markdown)

Protocol-and-compatibility.md

@@ -1,6 +1,7 @@
 # Protocol compatibility
 - Make sure LoRa sync word and other LoRa parameters match
 - **Normal/Client mode** should be interoperable with other clients, which transmit raw text APRS messages if KISS client sends them in this format to the modem
+  - NB! For interoperability with other APRS LoRa implementation, which do not use AX.25 frames, but use text based messages, need to use **TNC (plaintext TNC2)** APRSDroid connection protocol and set `cfg.EnableTextPackets/CFG_TEXT_PACKETS` to `true`
 - **Server iGate** by default supports only classical `AX25` frames over LoRa (as defined in http://www.aprs.org/doc/APRS101.PDF page 12, see section below). It should enable interoperability with classical Linux APRS software, such as Xastir with `kissattach`. Some LoRa ARPS implementations transfer plain text APRS messages over LoRa, for this mode operations need to set `cfg.EnableTextPackets/CFG_TEXT_PACKETS` to `true`, in this case iGate will transmit, receive and digirepeat text based APRS messages instead of classical ax25 frames.
 
 # APRS AX.25 protocol