Star Micronics 150 Serial Port Flow Control, Using DTR

Communications PcOS Series 150 Programmer's Guide

Serial Port

Page 118 Rev G12/14/99

Serial Port Protocol

The serial port supports two flow control standards, XON/XOFF and Ready/Busy (sometimes

called DTR or hardware handshake.)

When Ready/Busy flow control is selected, the printer can be configured to use DTR, RTS, or

both for flow control. If only DTR is selected for flow control, RTS will indicate that the printer

has faulted. The following discussions will assume the DTR is being used for flow control.

The Ready/Busy protocol generally uses the DTR signal to indicate to the host computer that the

printer is not ready to accept data. The host should stop sending data to the printer as soon as

possible. Because the host may not notice the DTR signal until it has transmitted several bytes of

data to the printer, the printer will continue to except up to 25515 bytes of data after it indicates

that it is not ready. The figure below illustrates how the Ready/Busy protocol works.

Serial

Communications

port

Data

Buffer emptying

Select key

Printer

control

software

Print

buffer

Serial Port Flow Control

Using DTR

RTS -> Request to send DTR -> Data terminal ready

data in

Serial

data out

(Not used for

flow control)

DTR

RTS

DTR

Clear

Set

Inquire

response

256 - 6K

Data

Buffer filling up

Data

High

speed

FIFO

ENQ response

Data

ENQ

proc.

Figure 20 Serial port flow control using DTR

15The buffer always signals it is full before it overflows. The size of the reserve depends on the buffer size

selected. It is always at least 255 bytes.

Contents

Main Page Programmers Guide PcOS Series 150 Change History Change History Disclaimer PcOS Series 150 Programmers Guide Disclaimer Copyright Trademarks Federal Communications Commission Radio Frequency Interference Statement Programmers Guide PcOS Series 150 Table of Contents Table of Contents Table of Contents PcOS Series 150 Programmer's Guide Programmer's Guide PcOS Series 150 Table of Contents Figures and Tables PcOS Series 150 Programmer's Guide Table of Figures Table of Tables Page Page Programmer's Guide PcOS Series 150 Overview Chapter 1: Overview of the Series 150 Printer Warranty Information Warranty Options Service Information What is in this book? Overview PcOS Series 150 Programmer's Guide Where can you find more information? Contacting Ithaca Peripherals Internet Support Programmer's Guide PcOS Series 150 General Description Chapter 2: General Description Series 150 Models Standard Features Page Programmer's Guide PcOS Series 150 General Specifications Chapter 3: General Specifications Printing Specifications Character Generation Page Physical Specifications Dimensions Weight Electrical Characteristics Self-powered AC Media Specifications Ribbon Receipt Paper Receipt/Journal Paper Printable Area Receipt Printing Paper tear-off Receipt Printing with the Autocutter Validation Forms Printing Validation - Top Insertion Validation - Left-side Insertion Validation Forms Insertion Control Codes Overview PcOS Series 150 Programmer's Guide Chapter 4: Control Codes Overview Nomenclature Programmer's Guide PcOS Series 150 Control Codes Overview Standard Emulation IPCL Codes EPOS Emulation Microline Emulation Application Development Tables and Charts Print/Paper Motion Chaper 5: Printer Control Codes Print/Paper Motion Low-level Paper Motion Control Horizontal Motion Horizontal Motion Control Horizontal Motion Vertical Motion Control Page Page Page Character Font Character Font Character Font International Character Sets and Code Pages 12/14/99 Rev G Page 25 Table 5 Language table IDs Page 26 Rev G12/14/99 Page Page Page Character Pitch Ithaca Peripherals Character Print Control Character Pitch Character Pitch Character Pitch Character Attribute Commands Page Page Page Page Page Page Control Codes PcOS Series 150 Programmer's Guide Print Rotation Commands Page Page Page Page Graphic Mode Standard APA Graphics Page Page Bar codes Page Page Receipt Paper Out Sensor Validation Operation Validation Operation Control Page Miscellaneous Control Page Page Page Printer Status Set/Inquire Parallel, Non-IEEE 1284 Mode Inquire Serial Mode Inquire Parallel, IEEE 1284 Mode Inquire Dynamic Response Mode Page Inquire Commands Page Page Page Page Page Extended Diagnostics Extended Diagnostic Commands EPOS Codes EPOS Codes Real-time Status EPOS Command Summary EPOS Codes Page 70 Rev G12/14/99 EPOS Deviations Command Descriptions Page Page Page MICROLINE Codes MICROLINE Codes MICROLINE Command Summary MICROLINE Codes Page 76 Rev G12/14/99 STAR Codes Star Codes Star Command Summary STAR Codes Page 78 Rev G12/14/99 NCR2567 Codes NCR2567 Codes NCR Command Summary TELPAR Codes Page 80 Rev G12/14/99 Telpar Codes Telpar Command Summary The following is a list of the Telpar commands that are supported. 12/14/99 Rev G Page 81 Control Codes Summary by Code Page 82 Rev G12/14/99 12/14/99 Rev G Page 83 Page 84 Rev G12/14/99 12/14/99 Rev G Page 85 Control Codes Summary by Function Page 86 Rev G12/14/99 12/14/99 Rev G Page 87 Page 88 Rev G12/14/99 Programmer's Guide PcOS Series 150 Operator Panel Controls Chapter 6: Operator Panel Controls Push Buttons - Momentary Switches Indicators Operator Panel Controls PcOS Series 150 Programmer's Guide Fault Indicators Programmer's Guide PcOS Series 150 Product Self-tests Chapter 7: Product Self-tests Level 0 Diagnostics Extended Diagnostics Self test Hex-dump Mode PcOS Series 150 Programmer's Guide Chapter 8: Hex-dump Mode Chapter 9: Configuration Mode Initial Power ON Manual Configuration Enable Remote Configuration Feature Configuration 12/14/99 Rev G Page 95 Page 12/14/99 Rev G Page 97 Page 12/14/99 Rev G Page 99 Page 100 Rev G12/14/99 12/14/99 Rev G Page 101 Page 102 Rev G12/14/99 General Control Page Vertical Control Character Interface Page Chapter 10: Communications Protocol and Print Buffers Overview Status and flow control back Data to printer Page Page Parallel Port Parallel Port Protocol Printer Buffer Size One-line mode Parallel Port Inquire IEEE 1284 Buffer Mode 4 Page Mode 0 Time-out Active State Inquire Responses Parallel Port Inquire (Non-IEEE 1284) Parallel Port Plug and Play Parallel Port Connector Signal Levels Serial Port Serial Port Features Serial Port Pin-out Signal levels Serial Port Protocol Serial Port Flow Control Using DTR 12/14/99 Rev G Page 119 Serial Port Flow Control XON/XOFF Figure 21 Serial port flow control XON/XOFF Print Buffer Flow Page Page Printer Buffer Size One-line Mode Serial Port Inquire Programmers Notes Remote Printer Reset Reset in Serial Mode Reset in Parallel Mode Power-cycle Recovery Remote Printer Reset Programmers Notes Programmers Guide PcOS Series 150 Cash Drawer Interface Chapter 11: Cash Drawer Interface Pin 1 Interface Description Interface Connectors Printing Graphics PcOS Series 150 Programmers Guide Chapter 12: Printing Graphics Character Graphics Programmer's Guide PcOS Series 150 Printing Graphics Printing Graphics PcOS Series 150 Programmer's Guide APA Graphics Programmer's Guide PcOS Series 150 Printing Graphics 12/14/99 Rev G Page 131 Page Programmer's Guide PcOS Series 150 Appendix A 12/14/99 Rev G Page 133 Appendix A Language Tables Appendix A PcOS Series 150 Programmer's Guide Page 134 Rev G12/14/99 Programmers Guide PcOS Series 150 Appendix B 12/14/99 Rev G Page 135 Appendix B ASCII Code Chart Table 20 ASCII chart Appendix C PcOS Series 150 Programmer's Guide Appendix C Ordering Cables General Information Programmer's Guide PcOS Series 150 Index 12/14/99 Rev G Page 137 Index [ Index PcOS Series 150 Programmer's Guide Page 138 Rev G12/14/99 A C D