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Rockwell Automation Publication 2080-UM002N-EN-E - November 2022
Appendix G Connect to Networks using DF1
Modem Control Line
Operation
The following explains the operation of the Micro800 controllers when you configure the RS-
232 serial port for the following applications.
DF1 Full-Duplex
When configured for DF1 full-duplex, the following control line operation takes effect:
No Handshake Selected
RTS is always inactive (low). Receptions and transmissions take place regardless of the state
of CTS input. Only make this selection when the Micro800 controllers are directly connected to
another device that does not require handshaking signals.
Full-Duplex (RTS always ON) Selected
RTS is always active (high).
Transmissions require CTS to be active.
DF1 Half-Duplex Slave
When configured for DF1 half-duplex slave, the following control line operation takes effect:
No Handshake Selected
RTS is always inactive. Receptions and transmissions take place regardless of the state of CTS
input. Only make this selection when the controller is directly connected to another device that
does not require handshaking signals.
Half-Duplex without Continuous Carrier (RTS/CTS) Selected
RTS is only activated during transmissions (and any programmed delays before or after
transmissions). Transmissions require CTS to be active.
DF1 Half Duplex Master
When configuring for DF1 half-duplex master, the following control line operation takes effect:
No Handshake Selected
RTS is always inactive. Receptions and transmissions take place regardless of the state of CTS
input. Only make this selection when the controller is directly connected to another device that
does not require handshaking signals.
Full-Duplex Modem (RTS always ON) Selected
RTS is always active (high).
Transmissions require CTS to be active.
Half-Duplex without Continuous Carrier (RTS/CTS) Selected
RTS is only active during transmissions (and any programmed delays before and after
transmissions).
Transmissions require CTS to be active