INSYS 56k Small INT 2.0, Руководство по эксплуатации

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INSYS Modem 56k small INT 2.0/USB 1.0 Functions
June 06 23
Hardware data flow control with the application (RTS):
Modem
RS232 Cable
RTS Line
Application
(E.g.: PC or con-
trol)
The application sets the RTS line to OFF to request from the mo-
dem to interrupt the data transmission.
It will depend on the according application software if the RTS/CTS
lines can be operated.
The application sets the RTS line to ON to request data from the
modem.
5.2.5 Software data flow control XON and XOFF
Modem
Send data
XON or XOFF character
Application
(E.g.: PC or
control)
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 ap-
plication. This character will cause the application to send no more
data.
It will depend on the according application software if the RTS/CTS
data flow control is supported.
After the modem has processed the input buffer so far, it will insert a
XON character into the data stream. This character will cause the
application to send data to the modem again. Analogously, the ap-
plicaiton can control the data stream from the modem to the appli-
cation.
The XON/XOFF method 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, …) are
transmitted, also for BTX operation or in the XMODEM transmission
protocol, for example, occasionally appearing XON or XOFF charac-
ters would disturb the operation.
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