In an ASCII system the print fields are sent to the printer exactly as supplied, so if the HSM has an 8-bit word format on the host AND an 8-bit word format to the printer, a X'80 from the host will be sent as X'80 to the printer. No interpretation or conversion is done. If either port is set up for 7-bit word format the MSB will be set to zero.

In EBCDIC systems, the print field data is assumed to be EBCDIC characters, and the HSM converts them to ASCII before sending them to the printer. Characters that are not defined in the EBCDIC character set will usually be converted to X'00, which most ASCII printers ignore.