You would actually send the following if using Serout2.
For Row 4 and Column 20
Serout2 pin, mode, [$1b, "[4;20H"]

Or you can do it all in hex.
Serout2 pin, mode, [$1b, $5b, $34, $3b, $32, $37, $48]

The ; is enclosed in quotation marks, so PBP will not treat it as a comment.