Functions
INSYS Pocket ISDN
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10.3
Data flow control
The data flow control ensures that the data transfer is interrupted as soon as the
buffer of the INSYS Pocket ISDN exceeds a certain level. There are two possibilities
for data flow control: via the control lines RTS and CTS, or via the control
characters XON/XOFF which are inserted into the data stream.
10.3.1
Hardware Data Flow Control (RTS/CTS)
The hardware data flow control works in two directions. When the critical buffer
level is exceeded, the INSYS Pocket ISDN will set the CTS line to "low" and will
thus indicate to the application to interrupt the data flow. When the buffer is
emptied sufficiently for the INSYS Pocket ISDN to be able to receive data again, the
CTS line is set to "high". Reversely, the application can also indicate to the INSYS
Pocket ISDN to interrupt the data flow. This is done via the RTS line. If it is set to
"low", the INSYS Pocket ISDN will interrupt the data flow to the application. The
application will set it to "high" to request data from the INSYS Pocket ISDN.
Data flow control is set to hardware as default setting.
Configuration with AT commands
Enable hardware data flow control
(RTS/CTS) with the command
AT&K=3
Disable data flow control with the
command
AT&K=0