And WTF is 'route syntax'? Plain English please, not geekspeak!
Apologies. I credited you with more erudition than you have. Syntax is Plain English. Geek is slang, originating in the 1800's.
Syntax, noun, the grammatical arrangement of words in a sentence
From the Latin syntaxis or the Greek suntaxis.
In the case of the AIS website the arrangement of words in the route box (i.e. it's syntax) follows the same rules that apply to an ICAO Flight Plan Route.
Acceptable
Navaid Identifier eg: POL - Polehill VOR
Airways Waypoint eg: FAWBO
Radial & Distance from a Navaid eg: SAM180030
LAT & LONG 7 character eg: 54N001W
LAT & LONG 11 character eg: 5430N00130W
Airways Route: can be used if flying IFR on an ATS route
NOT acceptable
ICAO/IATA/AIS Airport Location Indicators
Visual Reporting Points (VRP): Use LAT & LONG
Remember to start the Route box/field with DCT and place DCT between Route points and finally DCT at the end.
Alles klaar?
Mike