![background image](http://html.mh-extra.com/html/national-instruments/enet-232-series/enet-232-series_manual_708976196.webp)
Why do loopback tests of large data transfers
sometimes have problems?
In a typical loopback test, an external wrap plug is used to loop back
transmit signals to receive signals. In this configuration, data transmitted
is read back on the same serial port to test port communication.
Loopback programs often perform this data transfer using a single write
followed by a single read, and thus rely on driver software and serial
hardware buffering to hold the data between the two function calls.
However, these buffers are of finite size, and thus any data transfer that
exceeds the buffer size either times out, blocks (due to flow control), or
drops data. This behavior is a result of the test design and does not
represent a hardware or driver error. Buffer sizes vary between operating
systems and hardware, but typically range from 4–8 KB in size.
Содержание ENET-232 Series
Страница 1: ......
Страница 5: ...Using Help Conventions Navigating Help Searching Help Printing Help File Topics ...
Страница 17: ...How to Use this Help File To use this help file refer to the following flow chart and the appropriate topics ...
Страница 21: ...Serial Hardware Overview PCI Kits PXI Kits USB Kits ENET Kits ExpressCard Kits PCMCIA Kits ...
Страница 24: ...PCI 485I RS 485 two port isolated RS 485 four port isolated ...
Страница 27: ...PXI 8423 RS 485 two port isolated RS 485 four port isolated ...
Страница 63: ...Save Pending Changes To save your changes to this item click Save ...
Страница 65: ...Restore Defaults To reset the fields to their default values at any time click the Defaults button ...
Страница 98: ...0 LPVOID l_SerialInterface sizeof l_SerialInterface LPDWORD l_ByteCount NULL ...
Страница 127: ...2 PORT LEDs USB Serial Hardware LEDs ...
Страница 139: ...Connecting the Cables to a Four Port PXI Serial Board ...
Страница 141: ...67 58 50 41 33 24 16 7 TXD 9 RI 9 ...
Страница 167: ......
Страница 169: ......
Страница 171: ......
Страница 181: ...How many serial ports can I have on my machine You can have up to 256 serial ports ...
Страница 189: ...nslookup hostname If you still cannot communicate with your device contact National Instruments ...
Страница 201: ...Glossary Prefixes Symbols A B C D E F G H I K L M P R S T U V ...
Страница 203: ...Symbols degrees ohms percent ...
Страница 204: ...A A amperes ANSI American National Standards Institute ...
Страница 205: ...B b bits B bytes baud bits per second bps bits per second ...
Страница 206: ...C C Celsius COM Computer Output Microform used in reference to a communication port CTS clear to send ...
Страница 208: ...E EIA Electronic Industries Association EMI electromagnetic interference ENET Ethernet ...
Страница 209: ...F FCC Federal Communications Commission FIFO First In First Out ft feet ...
Страница 210: ...G G ground ...
Страница 211: ...H HSI handshake input HSO handshake output Hz Hertz ...
Страница 213: ...K Kbaud kilobits per second ...
Страница 214: ...L LED light emitting diode ...
Страница 215: ...M m meters MB megabyte ...
Страница 216: ...P PC personal computer PCI Peripheral Components Interconnect ...
Страница 218: ...S s seconds SCSI Small Computer Systems Interface ...
Страница 220: ...U UART Universal Asynchronous Receiver Transmitter ...
Страница 221: ...V V volts VDC volts direct current VXI VME eXtensions for Instrumentation ...
Страница 222: ...Important Information Warranty Copyright Trademarks Patents Warning Regarding Use of NI Products Compliance ...