Tested and working under Linux. I have no way to test this under windows.

If there is a windows problem, look very carefully at the line termination
with a serial port monitor.  It should be \r\n (CR-LF), not \n, not \r\r\n
or any other possible variant.

diff --git a/src/Network/AV400.cxx b/src/Network/AV400.cxx
index ee7b7fa73129e1a7df76c7788b34bbb37cd613fe..1a5cd6138d800c1dce6fc2ea17c75668fad5d70e 100644 (file)
--- a/src/Network/AV400.cxx
+++ b/src/Network/AV400.cxx
@@ -80,7 +80,7 @@ bool FGAV400::gen_message() {
     double min;
 
     // create msg_z
-    sprintf( msg_z, "z%05.0f\r\n", cur_fdm_state->get_Altitude() );
+    sprintf( msg_z, "z%05.0f\n", cur_fdm_state->get_Altitude() );
 
     // create msg_A
     sprintf( msg_A, "A");
@@ -94,7 +94,7 @@ bool FGAV400::gen_message() {
     }
     deg = (int)latd;
     min = (latd - (double)deg) * 60.0 * 100.0;
-    sprintf( msg_A, "A%c %02d %04.0f\r\n", dir, deg, min);
+    sprintf( msg_A, "A%c %02d %04.0f\n", dir, deg, min);
 
     // create msg_B
     double lond = cur_fdm_state->get_Longitude() * SGD_RADIANS_TO_DEGREES;
@@ -106,21 +106,24 @@ bool FGAV400::gen_message() {
     }
     deg = (int)lond;
     min = (lond - (double)deg) * 60.0 * 100.0;
-    sprintf( msg_B, "B%c %03d %04.0f\r\n", dir, deg, min);
+    sprintf( msg_B, "B%c %03d %04.0f\n", dir, deg, min);
 
     // create msg_C
+    float magdeg = fgGetDouble( "/environment/magnetic-variation-deg" );
     double vn = fgGetDouble( "/velocities/speed-north-fps" );
     double ve = fgGetDouble( "/velocities/speed-east-fps" );
     double gnd_trk_true = atan2( ve, vn ) * SGD_RADIANS_TO_DEGREES;
-    if ( gnd_trk_true < 0.0 ) { gnd_trk_true += 360.0; }
-    sprintf( msg_C, "C%03.0f\r\n", gnd_trk_true);
+    double gnd_trk_mag = gnd_trk_true - magdeg;
+    if ( gnd_trk_mag < 0.0 ) { gnd_trk_mag += 360.0; }
+    if ( gnd_trk_mag >= 360.0 ) { gnd_trk_mag -= 360.0; }
+    sprintf( msg_C, "C%03.0f\n", gnd_trk_mag);
 
     // create msg_D
     double speed_kt = sqrt( vn*vn + ve*ve ) * SG_FPS_TO_KT;
     if ( speed_kt > 999.0 ) {
         speed_kt = 999.0;
     }
-    sprintf( msg_D, "D%03.0f\r\n", speed_kt);
+    sprintf( msg_D, "D%03.0f\n", speed_kt);
 
     // create msg_E (not implemented)
     // create msg_G (not implemented)
@@ -129,24 +132,23 @@ bool FGAV400::gen_message() {
     // create msg_L (not implemented)
 
     // create msg_Q
-    float magdeg = fgGetDouble( "/environment/magnetic-variation-deg" );
     if ( magdeg < 0.0 ) {
         magdeg = -magdeg;
         dir = 'W';
     } else {
         dir = 'E';
     }
-    sprintf( msg_Q, "Q%c%03.0f\r\n", dir, magdeg * 10.0 );
+    sprintf( msg_Q, "Q%c%03.0f\n", dir, magdeg * 10.0 );
 
     // create msg_S (not implemented)
 
     // create msg_T
-    sprintf( msg_T, "T---------\r\n" );
+    sprintf( msg_T, "T---------\n" );
 
     // create msg_l (not implemented)
 
     // sentence type 2
-    sprintf( msg_type2, "w01%c\r\n", (char)65 );
+    sprintf( msg_type2, "w01%c\n", (char)64 );
 
     // assemble message
     string sentence;
@@ -156,21 +158,21 @@ bool FGAV400::gen_message() {
     sentence += msg_B;          // longitude
     sentence += msg_C;          // ground track
     sentence += msg_D;          // ground speed (kt)
-    sentence += "E-----\r\n";
-    sentence += "G-----\r\n";
-    sentence += "I----\r\n";
-    sentence += "K-----\r\n";
-    sentence += "L----\r\n";
+    // sentence += "E-----\n";
+    // sentence += "G-----\n";
+    // sentence += "I----\n";
+    // sentence += "K-----\n";
+    // sentence += "L----\n";
     sentence += msg_Q;          // magvar
-    sentence += "S-----\r\n";
+    // sentence += "S-----\n";
     sentence += msg_T;          // end of type 1 messages (must be sent)
     sentence += msg_type2;      // type2 message
-    sentence += "l------\r\n";
+    // sentence += "l------\n";
     sentence += '\003';         // ETX
 
-    cout << sentence;
-
+    // cout << sentence;
     length = sentence.length();
+    // cout << endl << "length = " << length << endl;
     strncpy( buf, sentence.c_str(), length );
 
     return true;