Automatic control function programming manual ladder language

12.7 Transmission Standards
The transmission standard is defined in the «format» argument of function comf() (see Sec. 12.2).
12.7.1 Before Software Index F
12.7.1.1 No Flow Control
No hardware or software signals are managed for transmission or reception.
Full duplex operation is possible.
12.7.1.2 RTS/CTS Flow Control
Signal RTS is managed during reception to stop and restart transfers. During transmission, RTS remains active while
the buffer is being transmitted.
Full duplex operation is impossible.
REMARK Signal RTS can be wired to CTS to ignore these signals and allow full duplex
operation without flow control.
12.7.1.3 Xon/Xoff Flow Control
During reception, the transfer is monitored by sending control characters on the transmission channel.
As soon as character DC1 (Xon) is sent by the receiver, the sender is authorised to send. When the receiver sends
character DC3 (Xoff), the sender has a time equal to transmission of 20 characters to stop transmission.
12.7.2 RS232 Standard
For software at index F or above.
12.7.2.1 No Flow Control
No hardware or software signals are managed for transmission or reception.
Full duplex operation is possible.
12.7.2.2 RTS/CTS Flow Control
For reception, signal RTS is controlled to monitor the line. This signal is not set by the sender.
As soon as this signal goes low, the sender must stop sending data. Only one more character can be sent after RTS
goes low.
As seen by the sender, transmission must be stopped when signal CTS goes low.
Full duplex operation is possible.
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