Black Box IC026A-R2, IC026AE-R2 manual Switch SW2 Enabling or Disabling Talk-Back on Timeout

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RS-232↔IEEE 488 INTERFACE CONVERTER

4.4.2TALK-BACK ON TIMEOUT

SW2-2 selects whether the interface converter should address the attached bus device to talk when the interface converter has no more serial data to send. This feature relies on time and not on terminators. Its use is primarily for simulating a serial plotter from an IEEE 488 (HP-IB) plotter. The factory default is Talk-Back On Timeout enabled.

1 2 3 4 5 6 7 8

OPEN

1 2 3 4 5 6 7 8

OPEN

Switch

Side

View

DOT

Talk-Back on	Talk-Back on
Timeout Disabled	Timeout Enabled

Figure 4-3. Switch SW2: Enabling or Disabling

“Talk-Back on Timeout.”

If Talk-Back on Timeout is enabled, the interface converter waits approximately 100 milliseconds after it detects that its serial input buffer is empty. If no serial character has been received by the end of this time, the IEEE bus device is addressed to talk. The choice of talk-back modes depends strongly on the type of device and software being used. For most plotter applications, the Talk-Back on Timeout feature should be enabled.

When the last IEEE bus terminator is detected from the IEEE device, the interface converter disables the device from sending additional information by asserting Attention (ATN) on the bus. If the IEEE device does not respond or finish transmission by the time additional characters are received into the serial input buffer, the talk sequence will be aborted to allow additional serial information to be sent to the IEEE device.

Most IEEE 488 plotters will not respond to the talk address sequence with output data unless there has been a specific device dependent command sent to tell them what to say. If they have not been told what to say, they say nothing.

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Contents RS-232↔IEEE Interface Converter RS-232↔IEEE 488 Interface Converter Trademarks Used in this Manual RS-232↔IEEE 488 Interface Converter NOM Statement RS-232↔IEEE 488 Interface Converter Contents RS-232↔IEEE 488 Interface Converter Contents Specifications IEEE-488 InterfaceSerial Interface Specifications GeneralIntroduction DescriptionAbbreviations Configuration Getting StartedInspection Serial PortSW3 Serial Port Settings Switch SW1 Selecting the Serial Baud Rate Switch SW1 Selecting the Serial Word Length Data Bits Switch SW2 Selecting the Serial Parity Switch SW1 Selecting the Serial Handshake Switch SW2 Selecting the Serial Terminator Selecting Terminator SubstitutionSelecting the Mode Switch SW3 Selecting the Ieee Bus Terminator10. Switch SW2 Selecting the Mode Selecting the Ieee AddressFeature Selections Serial Interface 15. Selecting RS-232 or RS-422 Signal Levels RxD Receive Data-Input-Pin TxD Transmit Data-Output-PinClear To Send-Input-Pin Request To Send-Output-PinVtest Test Voltage-Output-Pin Gnd Ground-Pin+RxD Receive Data Plus-Input-Pin +TxD Transmit Data Plus-Output-PinRTS CTS General DSR RTS CTSGetting Started Controller Operation Controller-Mode Serial to Ieee OperationSerial and Ieee Terminator Substitution Talk-Back Features Ieee Address SelectionSwitch SW1 Enabling or Disabling Talk-Back on Terminator Switch SW2 Enabling or Disabling Talk-Back on Timeout 7470A SP1PA1000,1000PDPA1000,6000PUSP0Plotter Applications A PC-Based Graphics System SW3 MacPlot Configuration Screen Setting the Internal DIP Shorting Jumper for RS-422 SW3 Printer Applications Peripheral Operation Peripheral-Mode OperationSerial and Ieee Input Buffers Ieee Data Transfers Controlled BUS Data Transfers Serial-Poll Status-Byte Register DIO8 Ieee Input Buffer not EmptyRsv Not Defined-AlwaysSerial Input Buffer not Empty Ieee Input Buffer FullUse of Serial and Bus Terminators Ieee 488 Bus ImplementationUntalk UNT SW3 View for Ieee Address Selection Ieee 488 Primer HistoryGeneral Structure RS-232↔IEEE 488 Interface Converter Send It to My Address DMMBus Management Lines Handshake Lines Data Valid DAVMultiline Commands Data LinesTalk Address Group TAG More on Service Requests Serial Poll Theory of Operation Address Device Part Number FunctionBoard Layout Component Layout of the Interface Converter’s MotherboardRED BLK Appendix A. Sample Dumb-Terminal Program CLSMultiline Messages SOHHow To Read the Chart Ascii CharacterIndex DIO1 DIO2 DIO3Index SW1 Copyright 1998. Black Box Corporation. All rights reserved