1. A printer processing method comprising: providing a printer with a mark-up language parsing unit interpreting mark-up language data written in a mark-up language; wherein: the printer receives first mark-up language data from (POS) application; the mark-up language parsing unit executes a first binary data conversion step for converting the first mark-up language data received from the POS application to first binary data executable by the printer based on model-dependent information that is specific to the printer and that defines conversion rules for character attributes and printer control commands, and executes a second binary data conversion step for converting second binary data generated by the printer to second mark-up language data based on the model-dependent information that is specific to the printer, and that further defines a rule for converting the second binary data to the second mark-up language data; the second mark-up language data is sent to the POS application; the second binary data generated by the printer is printer status information; the POS application runs on a host device remote from the printer; the first mark-up language data is part of a first mark-up language document output from the POS application, the POS application executing a transaction process and generating transaction data; the mark-up language parsing unit further executes a status information conversion step for converting the printer status information to the second mark-up language data based on the model-dependent information that is specific to the printer and that defines the rule for converting the second binary data to the second mark-UP language data; and when the second mark-up language data is sent to the POS application, the second mark-up language data is sent as a second mark-up language document to the POS application.
1. A printer processing method comprising: providing a printer with a mark-up language parsing unit interpreting mark-up language data written in a mark-up language; wherein: the printer receives first mark-up language data from (POS) application; the mark-up language parsing unit executes a first binary data conversion step for converting the first mark-up language data received from the POS application to first binary data executable by the printer based on model-dependent information that is specific to the printer and that defines conversion rules for character attributes and printer control commands, and executes a second binary data conversion step for converting second binary data generated by the printer to second mark-up language data based on the model-dependent information that is specific to the printer, and that further defines a rule for converting the second binary data to the second mark-up language data; the second mark-up language data is sent to the POS application; the second binary data generated by the printer is printer status information; the POS application runs on a host device remote from the printer; the first mark-up language data is part of a first mark-up language document output from the POS application, the POS application executing a transaction process and generating transaction data; the mark-up language parsing unit further executes a status information conversion step for converting the printer status information to the second mark-up language data based on the model-dependent information that is specific to the printer and that defines the rule for converting the second binary data to the second mark-UP language data; and when the second mark-up language data is sent to the POS application, the second mark-up language data is sent as a second mark-up language document to the POS application. 2. The printer processing method of claim 1 , wherein: the printer prints based on the generated transaction data; the model-dependent information is one of multiple sets of model-dependent information, each corresponding to a different device model, and stored within a memory of the printer; and the model-dependent information used in converting the printer status information to the second mark-up language data is selected from among the multiple sets of model-dependent information based on device-model information of the printer.