Abstract: A host computer checks the frequency of type data such as a character code or a graphic pattern in print data. Type data with a high frequency is registered in a registered character management area in correspondence with a data ID and sent to a printer. The printer registers the received ID and data in a print data registration area. Thereafter, the host computer sends print data obtained upon replacement of the type data with the ID to the printer. The printer identifies an ID included in the print data, replaces the ID with the corresponding type data, and outputs the print data. With this processing, data with a high use frequency can be registered in the printer. Therefore, the data transfer amount from the host computer can be decreased, and the printing processing speed is increased. In addition, since the frequency is totalized, the memory in the printer can be effectively used.

Abstract: A command information transfer method and system capable of transferring command information by discriminating it from data information, and capable of using protocols of IEEE P1284, when a nibble or byte mode is incorporated which is stipulated by IEEE P1284 as bi-directional parallel I/F. A new communication mode simulating the extensibility link is set by an extensibility request value undefined by IEEE P1284 and command information is transferred at the second and following bytes of such multiple-byte negotiation. An nFault signal is used for both a notice of error and for a reverse direction information transfer request.