To be compatible with the original HP package, the PCL fonts in this package do not have human readable text characters. It is easy to add text with a separate print command. The following example select the default font (command <esc>(3@ ), and print the human readable below the barcode:

fprintf(prn, "\0x1B(0Y\0x1B(s0p4h12.0");
fprintf(prn, "*PN18906*");
fprintf(prn, "\0x1B(3@\n");
frpintf(prn, "PN18906");