XON/XOFF Protocol, DTR/DSR Protocol | Epson A794-D100 specification

Chapter 5: Communication Interface

A794 Owner’s Guide

XON/XOFF Protocol

The XON/XOFF characters coordinate the information transfer between the printer and the host computer. The printer sends an XON character when it is ready to receive data and it sends an XOFF character when it cannot accept any more data. The software on the host computer must monitor the communication link as shown in the following flowchart in order to send data at the appropriate times.

If XON/XOFF has been selected, the printer also toggles the DTR signal, as described in the next section, but it does not look at the DSR signal to transmit data.

XON character = hexadecimal 11.

XOFF character = hexadecimal 13.

DTR/DSR Protocol

The DTR signal is used to control data transmission to the printer. It is driven low when the printer is ready to receive data and driven high when it cannot accept any more data. Data is transmitted from the printer after it confirms that the DSR signal is low.

36	March 1999

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Epson A794-D100 manual XON/XOFF Protocol, DTR/DSR Protocol

Contents

Owners Guide Page Legal Notices Disclaimer Power Supply Contents Communication Interface Programming Information Installations Features OptionsDescription of Printer Models Available Description of Printer Models Available Model IdentificationCommunication Interfaces Installations Setting up the printer Features On a Flat Surface Vertically see note Options Using the Printer Printer Controls Changing Paper Testing the Printer Reset Button Printer ControlsPaper Feed Button Tone Changing Paper A794 Owner’s Guide Paper jams Troubleshooting the Printer Testing the Printer Poorly printed test printout Troubleshooting the Printer Troubleshooting the Printer Printer Tone and Green LED Printing Problems Printer Does Not Work Ordering Thermal Paper Ordering Miscellaneous Supplies Ordering Thermal Paper Thermal Paper SpecificationsHow to Order Manufacturers Ordering Power Supply and Power Cord Ordering Miscellaneous SuppliesOrdering Cash Drawers Ordering Communication Cables Wall-Mount Kit Paper Specifications Print Zones CharactersCharacter Sets Size CharactersPrint Modes Standard Paper Specifications Print ZonesPrint Zones for 80 mm Paper Print Zones for 82.5 mm Paper Character Sets Code Code Code Code Code Code Code Code Communication Overview RS-232C Interface Using Basic to Send Commands Sending CommandsUsing DOS to Send Commands Communication Overview RS-232C Interface Print Speed and Timing XON/XOFF Protocol DTR/DSR Protocol Power Connector RS-232C Technical SpecificationsCommunication Connectors Pin DB-9 Connector Pin DB-25 Connector Cash Drawer Connector RS-232C Settings Ieee Bi-directional Parallel Connector Parallel Interface Communication Interface List of Commands Comparisons Command Descriptions Programming Information List of Commands Programming Information 26 s c1 c2 n1 d1...nn dn NL nH Comparisons 1D 2A n1 n2 d1...dn Command Descriptions Command Conventions Perform Full Knife Cut Printer Function CommandsClear Printer Hexadecimal Decimal Exceptions Hexadecimal Perform Partial Knife CutGenerate Tone Decimal Formulas Select Print Mode Value of n Hexadecimal Decimal Default Select Peripheral Device for Multi-DropInitialize Printer Select Paper Sensors to Output Paper End Signals Default of n ExceptionsRange of n Enable or Disable Panel Button Select Sensors to Stop Printing Range of k Read from Non-Volatile MemoryGenerate Pulse to Open Cash Drawer Value of p1 Value of n1 Select Cut Mode and Cut PaperWrite to Non-Volatile Memory Nvram Value of n2 Activate Carriage Return Vertical Positioning and Print CommandsPrint and Feed One Line Feed n Print Lines Range of n Default Feed n Dot RowsAdd n Extra Dot Rows Print Set ColumnSet Line Spacing to 1/6 Inch Set Line Spacing Print and Feed Paper Print and Feed n Lines Horizontal Positioning Commands Horizontal TabSet Right-Side Character Spacing Set Absolute Starting Position Value of k Default Set Horizontal Tab Positions Set Relative Print Position Select Justification Compatibility Information A794 receipt vs. A793 receipt Set Left Margin Range of nLRange of nH Set Horizontal and Vertical Minimum Motion Units GS P x y Set Printing Area Width Print Characteristics Commands Select Double-Wide CharactersSelect Single-Wide Characters Select 90 Degree Counter-Clockwise Rotated Print Select Pitch Column WidthHexadecimal Decimal Related Information Select Character Set Define User-Defined Character Set Values and Ranges Select or Cancel Underline Mode Cancel User-Defined Character Copy Character Set from ROM to RAMESC 0 0 Select or Cancel Emphasized Mode Select or Cancel Double Strike Select or Cancel Italic Print Select Character Code Table Select or Cancel 90 Degree Clockwise Rotated Print Select or Cancel Upside-Down Print ModeSelect International Character Set Select Or Cancel White/Black Reverse Print Mode Select or Cancel Smoothing Mode Select Superscript or Subscript Modes Summary of Rotated Printing Download BMP Logo Graphics CommandsPrint Raster Graphics Hexadecimal Decimal Value = Number of dots to be moved from the beginning of the line Select Bit Image Mode Select Single-Density Graphics Select Double-Density Graphics Select the Current Logo Define Downloaded Bit Image Ranges Hexadecimal 1D 2F m Decimal Print Downloaded Bit ImageConvert 6 Dots/mm Bitmap to 8 Dots/mm Bitmap Value and Range of m Printer Status Commands Request Alternate Status parallel printers only Transmit Peripheral Device Status RS-232C printers only Transmit Paper Sensor Status Hexadecimal Decimal Values Transmit Printer ID Hexadecimal 1D 49 n Decimal Transmit Printer ID, Remote Diagnostics Extension Values of n Programming Information A794 Owner’s Guide Select or Cancel Automatic Status Back ASB Default ASB disabled Exceptions Undefined Off Not used. Fixed to off Transmit Status When n is out of the specified range, the command is ignored Send Printer Software Version Print Test FormAX t Real Time Commands Rules for Using Real Time Commands Busy Line and Fault Conditions Moving Data through the Buffer Recognizing Data from the Printer Real Time Request to Printer Real Time Status Transmission Related Information = Transmit Printer Status = Transmit Error Status = Transmit RS-232C Busy Status = Transmit Receipt Paper Status Real Time Printer Status Transmission Hexadecimal Decimal Value of Byte Bar Code Commands Select Printing Position of HRI CharactersSelect Pitch of HRI Characters Select Bar Code Height Print Bar Code UPC-A Default Formulas Select Bar Code Width Cancel Print Data in Page Mode Mode CommandsPrint and Return to Standard Mode Hexadecimal 0C Decimal Exceptions Hexadecimal 1B 0C Decimal Exceptions Print Data in Page ModeSelect Page Mode Hexadecimal 1B 4C Decimal Exceptions Select Standard Mode Ascii ESC S Select Print Direction in Page Mode Default Exceptions Set Print Area in Page Mode Select Character Size Set Absolute Vertical Print Position in Page Mode Set Relative Vertical Print Position in Page Mode Macro Commands Select or Cancel Macro DefinitionHexadecimal 1D 3A Decimal Formulas Execute Macro Value of rValue of t Flash Download Commands Printer operation Return Segment Number Status of Flash Memory Switch to Flash Download ModeReturn Boot Sector Firmware Part Number ESC Get Firmware CRC Return Boot Sector CRCSelect Flash Memory Sector to Download Range of n Exceptions Erase All Flash Contents Except Boot Sector Return Main Program Flash CRCErase Selected Flash Sector Download to Active Flash Sector Ch * 256 + cl Ffff hexadecimal March 127 Reset Firmware Erase User Flash Sector Index Basic 130 March March 131 132 March