they're actually not a part of the syntax, it's more of a Crestron thing - we were told way back when in P101 it's the 'preferred' way, kind of best-practice, that all strings and especially the ones with mixed ASCII/hex characters are enclosed within quotes on the Crestron side of things, i. e. when they are entered in SIMPL symbols. so no, the command is actually ka 01 01\x0d, but when you enter it into a SIO symbol it's recommended that you add the quotes.
