i-modul Modem 144/56k
Functions
6.4.2
Software data flow control (XON/XOFF)
When the input buffer of the modem exceeds a certain fill state, the modem will
insert an XOFF character into the data stream to the application. This character will
cause the application to send no more data. It will depend on the according
application software if the XON/XOFF data flow control is supported.
After the input buffer of the modem is emptied so much that data can be received
again, the modem will send an XON character to the application. This character will
cause the application to send data to the modem 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
To switch the data flow control on and to
set the type to XON/XOFF, use:
AT&K4
To switch the data flow control off, use:
AT&K0
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