NCR 7197 Owner's Manual

Also see for 7197: Owner's manual Guide Parts Identification Manual Owner's manual Wi-fi configuration guide

Contents

NCR 7197 Owner's Manual Manual pdf 155 page image

7197 Owner’s Guide Chapter 6: CommandsNovember 2002 137Real Time CommandsThese commands provide an application interface to the printer even when the printer isnot handling other commands (RS-232C communication interface only):1. Real Time Status Transmission (GS Sequence and DLE Sequence)2. Real Time Request to Printer (GS Sequence and DLE Sequence)3. Real Time Printer Status TransmissionThe Batch Mode Printer Status commands are placed in the printer’s data buffer as theyare received and handled by the firmware in the order in which they are received. If thepaper exhausts while printing data that was in the buffer ahead of the status command,the printer goes busy at the RS-232C interface and suspends processing the data in thebuffer until paper is reloaded. This is true for all error conditions: knife home error,thermal print head overheat, etc.The Real Time commands are implemented in two ways to correct these problems. Bothimplementations offer the same functionality; which one you choose depends on thecurrent usage of your application.Preferred ImplementationFor a new application the GS (1D) sequences are recommended to avoid possiblemisinterpretation of a DLE (0x10) sequence as a Clear Printer (0x10 0, ASCII DLE NUL)command.An application using these GS (1D) sequences, does not need to distinguish for the printerbetween the new real time commands and the Clear Printer command. Thisimplementation is ideal for an existing 7193 application that already uses the Clear Printercommand or for a new application being developed.Alternate ImplementationThe alternate implementation uses the DLE (0x10) sequences as implemented on otherprinters. An application using these DLE (0x10) sequences and the original 7193 ClearPrinter command (0x10) must distinguish for the printer between the new real timecommands and the Clear Printer command by adding a NUL (0x00) to the Clear Printercommand.An application using these DLE (0x10) sequences must also send the second byte of thesequence within 100 milliseconds of the first, to prevent the first byte being mistaken for aClear Printer command.Rules for Using Real Time CommandsThree situations must be understood when using real time commands.First, the printer executes the Real Time command upon receiving it and will transmitstatus regardless of the condition of the DSR signal.Second, the printer transmits status whenever it recognizes a Real Time StatusTransmission command sequence, even if that sequence happens to occur naturally withinthe data of another command, such as graphics data.In this case the sequence will also be handled correctly as the graphics data it is intendedto be when the graphics command is executed from the buffer.