This is copied from the log window;
14:52:21.852 : ok T:55.7 /214.0 B:33.5 /60.0 T0:55.7 /214.0 T1:95.3 /0.0 T2:109.4 /0.0 F:100 R:100 @:0 B@:0
14:52:22.866 : ok T:56.1 /214.0 B:33.3 /60.0 T0:56.1 /214.0 T1:95.0 /0.0 T2:109.2 /0.0 F:100 R:100 @:0 B@:0
when slicing (Cura or Prusa) the extruder is selected with the T0, T1, T2 gcode (tool select). I'm going to ask Geeetech to get the source code (it's not on their site). Others have asked for it too but I'm not sure why Geeetech isn't sharing as freely as other controller cards they've made. This one is based on the STM32F103 processor unlike previous controllers that used Atmel processors. I would think sending out the value that is depicted in T0 for T1 and T2 would be a work around for now and probably not that difficult.