Module17 and OpenRTX Modifications (Part 2)
As promised here is part 2 of my blog concerning OpenRTX and the Module17 board. I have for now moved onto M17 itself. First I added Meta text to outgoing voice transmissions. Meta text is similar to D-STAR slow-speed text in that it is visible to the receiver on their radio display. D-STAR is limited to about 21 characters where as M17 allows up to 52. Having the capability of transmitting such long messages left me with the problem of how to show it on displays with a width limit of about 20 characters depending on font size. My solutions was to create a function to slowly scroll the text from right to left wrapping back to the right if needed. This works fairly well so long as the message is received in tact otherwise the text jumps around a bit. This is known as meta text because it is part of the LSF frame in M17 protocol. An LSF frame is the first frame in all M17 transmissions and in addition to meta text it contains the transmission type, and source and destination call-signs. ...
