Software Data Flow Control (Xon/Xoff) - insys icom 56k Manual

Ac/dc 4.2

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Functions

11.6.2

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

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 HSComm

Select the type of data flow control or switch it off completely on the tab

Modem in the panel "Handshake" (Page 36, Figure 7: HSComm Modem -

Modem, Position 26).

Configuration with AT commands

To switch the data flow control on and to

set the type to XON/XOFF, use:

To switch the data flow control off, use:

INSYS Modem 56k AC/DC 4.2

AT&K4

AT&K0

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