Communication Flow Control; Flow Control During Transmit; Flow Control During Receive - Yamaha RCX141 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", the 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 the functions
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 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 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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