Communication Flow Control; Flow Control During Transmit; Flow Control During Receive - Yamaha RCX40 User Manual

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NOTE
1) Transmission stops when
transmission is disabled in either
of XON/XOFF or RTS/CTS flow
control.
2) CTS must be on during
transmission regardless of flow
setting. When RTS/CTS is set to
"No", CTS should always be set
on. However, if CTS is connected
to RTS of the other party, CTS may
not always be on causing the
transmission to halt, depending on
the other party specifications.
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NOTE
The flow controls function separately.
For instance, when all flow controls
are set to "Yes" and the receive buffer
capacity is low, an XOFF is
transmitted, and RTS is turned off.
Later, when the receive buffer capacity
is restored, an XON is transmitted, and
RTS is turned on.
3.3

Communication flow control

Software flow control (XON/XOFF) and hardware flow control (RTS/CTS) methods can
be selected by specifying the communication parameters.
3.3.1

Flow control during transmit

XON/XOFF, DSR and CTS indicate whether the other party can receive data.
Flow Control
Temporarily stops transmission when
XOFF is sent from the other party.
XON/XOFF
Resumes transmission when XON is
sent.
Stops transmission while CTS is OFF.
RTS/CTS
3.3.2

Flow control during receive

To prevent overflow when receiving data, XOFF, DTR and RST are used to notify the
other party that this end is busy.
Flow Control
Transmits XOFF when available space
in receive buffer falls below a certain
capacity.
XON/XOFF
Transmits XON when receive buffer is
empty.
Turns RTS off when available space in
receive buffer falls below a certain
capacity.
RTS/CTS
Turns RTS on when receive buffer is
empty.
3. Communication specifications
Yes
XON (11H) and XOFF (13H) do not affect
transmission even when they are received.
Stops transmission while CTS is OFF.
Yes
XON and XOFF are not transmitted.
XON and XOFF are ignored if received.
RTS is always on.
No
No
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