Thanks for advices, I think I can go with Heckler's example. I'll give it a try .

correct me if I get it wrong, it waits for "$GPRMC," string, and then writes first byte to hh second to mm third to ss and then again waits for "," but there are dec4 and dec3 variables too, like latminn and longdeg, they can exceed 1 byte. So how 4 digits decimal value writed to latminn?

[QUOTE=Heckler;135804]

Code:
SerIn2 PORTA.0,188,3000,tmout,[wait("$GPRMC,"),DEC2 hh,DEC2 mm,dec2 ss,_
  wait(","),fix,wait(","),DEC2 latdeg,DEC2 latmin,wait("."),dec4 latminn,_
  wait(","),NS,wait(","),DEC3 londeg,DEC2 lonmin,wait("."),dec4 lonminn,_
  wait(","),EW,wait(","),dec knots,dec knotsten,dec course,_
  wait(","),DEC2 dy,DEC2 mt,DEC2 yr]
Code:
if fix="V" then goto nofix