Updated Protocol and compatibility (markdown)

Protocol-and-compatibility.md

@@ -32,7 +32,7 @@ Arduino code to generate compressed coordinates from degrees.
 **  Convert degrees in long format to APRS compressed format
 **  http://www.aprs.org/doc/APRS101.PDF, page 36
 */
-static char conv_buf[32];
+static char conv_buf[5];
 char* deg_to_compressed(long deg, boolean is_lat) {
   long tmp;
   if (is_lat) {