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Flow Control
Your modem supports RTS/CTS, XON/XOFF and Transparent XON/OFF flow control. Flow
control ensures that data is not lost between your computer and your modem. Flow control will
be ignored when your modem is configured for variable speed mode (AT\N1) or is in local
command state.
RTS/CTS Flow Control
RTS/CTS flow control takes place when the modem and computer manipulate the CTS (Clear
To Send) and RTS (Request To Send) signals to stop and start data flow. This form of flow
control is recommended if supported by your computer and communications software, as it
does not interfere with file transfer protocols.
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In order for flow control to operate correctly between your computer and the
modem, the appropriate form of flow control must be selected with your
communications software. See your communications software manual for details.
You must also have a modem cable that connects the RTS and CTS signals of your
modem to your computer.
RTS/CTS flow control is selected with the &K3 command.
XON/XOFF Flow Control
XON/XOFF flow control takes place when the modem and communications software transmit
XON and XOFF characters to start and stop data flow. This form of flow control is only
recommended when your computer or communications software does not support RTS/CTS
flow control. The ASCII values of the XON/XOFF characters are 17 (DC1) and 19 (DC3)
respectively.
XON/XOFF flow control is selected with the &K4 command.
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XON/XOFF flow control should not be used with the XModem, YModem or
SEAlink file transfer protocols.
Transparent XON/XOFF Flow Control
Transparent XON/XOFF flow control is identical to normal XON/XOFF flow control except
the XON and XOFF characters which are part of the normal data stream are encoded to allow
flow control with file transfer protocols such as XModem. The ASCII values of the XON and
XOFF characters are 17 (DC1) and 19 (DC3) respectively.