A Table Reference Code is the second byte in a line data stream.
It is used to bring more dynamic into a formatted document and have the input data control the appearance of a form.
The PPFA language supports the TRCREF command that allows to map a particular font to the Channel that is selected in the input data.
There is a hierarchy to the sequence by which the font selection is observed. The TRC is the second one before the FIELD level later in the formatting hierarchy has the highest priority.
If a TRC is used then the second character in every input record is considered as a TRC Code.