Since this has come up a couple of times, I decided to publish the escape characters for an HL7 message:
\H\ start highlighting
\N\ normal text (end highlighting)
\F\ field separator
\S\ component separator
\T\ subcomponent separator
\R\ repetition separator
\E\ escape character
\Xdddd\ hexadecimal data
\Zdddd\ locally defined escape sequence
The escape sequences for field separator, component separator, subcomponent separator, repetition separator, and escape character are also valid within an ST data field.
No escape sequence may contain a nested escape sequence.