Functions
i-modul ISDN HIX V4
6.3.2
Software Data Flow Control with XON/XOFF
When the input buffer of the i-modul ISDN HIX V4 exceeds a certain fill state, the i-
modul ISDN HIX V4 will insert an XOFF character into the data stream to the
application. This character will cause the application to send no more data. It
depends on the according application software if the XON/XOFF data flow control
is supported.
After the input buffer of the i-modul ISDN HIX V4 is emptied sufficiently that data
can be received again, the i-modul ISDN HIX V4 will send an XON character to the
application. This character will cause the application to send data to the i-modul
ISDN HIX V4 again. Analogously, the application can insert XON/XOFF characters
into the data stream to switch the data flow on and off. The XON/XOFF data flow
control is only available when the transmitted data do not contain the characters
XON or XOFF, which usually appear only in actual ASCII texts (7 bit). When binary
data (programs, etc.) are transmitted, or in the XMODEM transmission protocol, for
example, occasionally appearing XON or XOFF characters would disturb the
operation.
Configuration with AT commands
Enable the software data flow control
XON/XOFF with the command
AT&K=4
Disable the data flow control with the
command
AT&K=0
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