Updated Protocol and compatibility (markdown)

Protocol-and-compatibility.md

@@ -20,7 +20,7 @@ At the link level, APRS uses the AX.25 protocol, as defined in AmateurPacket-Rad
 - Frame Check Sequence — The FCS is a sequence of 16 bits used for checking the integrity of a received frame.
 
 # APRS TNC2 text protocol
-TNC2 protocol does not use KISS, it sends text based APRS messages, multiple messages are separated by using new line character `\n`.
+TNC2 protocol does not use KISS, it sends text based APRS messages, multiple messages are separated by using new line character `\n`. This is quite inefficient protocol for LoRa, because packet lengths are much longer than AX25, especially if compressed packets are used, which causes longer TOA (time on the air).
 
 # Bluetooth terminal applications
 Set `cfg.EnableTextPackets/CFG_TEXT_PACKETS` to `true` to use modem for sending text based messages through Bluetooth terminal applications.