How do I embed a PCL escape character sequence within a check RTF template? (signature printing)

On Payables 12.2.5 we have been using the seeded RTF check template named "Standard Check Format (Stub After Payment)", code=IBYDC_STD1A to print to pre-printed check stock, with signature endorsement happening as a separate process that does not involve EBS in any way.

I'm looking at TROY printers to print a signature on the check at the time it is printed, which they say can be achieved by buying their custom printers holding the custom signature, then embedding a certain PCL escape character sequence within the RTF at the position of the signature area, which is picked up by the printer and translated to the image of the signature stored inside the printer.