+1 on sailias comments, plus I will add mine, I wanted to log the openCPN´s output at the autopilot´s com port, and I realized that you need to have an active waypoint or
route for RMC sentence to appear, otherwise (no waypoint no route) there will be no position data outputting. This sums up another problem to an already convoluted task, you have to remember to activate a waypoint even if you dont want to, just to get LL into the VHF.
Just for reference this is a small log:
NMEA log from 11/8/11 12:30
$ECRMC,152916,A,3358.573,S,05801.881,W,5.000,315.0 00,120811,-0.000,E*45
$ECRMB,A,0.033,L,001,,3357.798,S,05802.913,W,1.155 ,312.165,5.000,V*2E
$ECRMC,152917,A,3358.572,S,05801.883,W,5.000,315.0 00,120811,-0.000,E*47
$ECRMB,A,0.033,L,001,,3357.798,S,05802.913,W,1.153 ,312.162,5.000,V*2F
$ECRMC,152918,A,3358.571,S,05801.884,W,5.000,315.0 00,120811,-0.000,E*4C
$ECRMB,A,0.033,L,001,,3357.798,S,05802.913,W,1.152 ,312.159,5.000,V*26
$ECRMC,152919,A,3358.570,S,05801.885,W,5.000,315.0 00,120811,-0.000,E*4D
$ECRMB,A,0.033,L,001,,3357.798,S,05802.913,W,1.151 ,312.155,5.000,V*29
$ECRMC,152920,A,3358.569,S,05801.886,W,5.000,315.0 00,120811,-0.000,E*4C
$ECRMB,A,0.033,L,001,,3357.798,S,05802.913,W,1.149 ,312.152,5.000,V*27
$ECRMC,152921,A,3358.568,S,05801.887,W,5.000,315.0 00,120811,-0.000,E*4D
$ECRMB,A,0.033,L,001,,3357.798,S,05802.913,W,1.148 ,312.148,5.000,V*2D
$ECRMC,152922,A,3358.567,S,05801.889,W,5.000,315.0 00,120811,-0.000,E*4F
$ECRMB,A,0.033,L,001,,3357.798,S,05802.913,W,1.146 ,312.145,5.000,V*2E
NMEA log to 11/8/11 12:30
regards. alex