National Instruments GPIB-232CV, Руководство пользователя

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Chapter 3 Operation
© National Instruments Corp. 3-9 GPIB-232CV User Manual
XON/XOFF
If your serial device does not recognize the hardware handshake scheme, or
if your application software uses the XON/XOFF handshake scheme, it may
be necessary to enable the XON/XOFF handshaking protocol. This
handshaking protocol performs the same function as the hardware
handshake but does so by sending special control codes over the data lines
instead of by changing logic levels on dedicated control lines.
When you enable the XON/XOFF protocol, the GPIB-232CV sends the
XOFF character (decimal 19 or <CTRL>s) when its internal buffer
becomes full. Once the GPIB-232CV is able to start receiving characters
again, it sends the XON character (decimal 17 or <CTRL>q). Similarly, if
the GPIB-232CV is transmitting data and receives the XOFF character, it
suspends transmission of any further data until it receives the XON
character.
Caution: Do not use XON/XOFF handshaking if you are transmitting
binary data. Because your data could include decimal 17 or 19
(<CTRL>q or <CTRL>s), the GPIB-232CV might handshake
erratically.