Functions
INSYS GSM 4.3
12.6.2
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 appli-
cation 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 applica-
tion 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 ac-
tual 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 HSComm
Select the type of data flow control or switch it off completely on the
"Basic Settings" tab in the "Handshake" panel.
Configuration with AT commands
To switch the data flow control on and to
set the type to XON/XOFF, use
AT\Q1
To switch the data flow control off, use
AT\Q0
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