Software Data Flow Control With Xon/Xoff - insys icom Pocket ISDN Manual

INSYS Pocket ISDN
10.3.2

Software Data Flow Control with XON/XOFF

When the input buffer of the INSYS Pocket ISDN exceeds a certain fill state, the
INSYS Pocket ISDN 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 INSYS Pocket ISDN is emptied sufficiently that data
can be received again, the INSYS Pocket ISDN will send an XON character to the
application. This character will cause the application to send data to the INSYS
Pocket ISDN 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
Disable data flow control with the
command
AT&K=4
AT&K=0
Functions
35