modbus RTU with TTL output

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m_electronic

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Hi,

I want to connect to a device with ttl output(modbus RTU).(I use Avr micro controller )
So I see these pins on it:
GND

· DTR

· TX

· RX

· +5Vdc

What's DTR pin? how can i connect to it with this micro controller?


Thank you
Best Regards
 

Do you have any datasheet?
I have interface Modbus with RS485 connection. Besides pin GND, TX and RX, there is 1 more pin (RE/DE) to set transmit/receive. Because the communication is half-duplex that can't transmit and receive at the same time. That is extra pin needed.
I don't know how your case.
 

Thank you for your kind information.
I think your answer is correct for my problem.
please tell me about this pin. you can read when you write 1 in it or with zero ?


Best Regards
 

A single MODBUS device with TX/RX pins won't need a DTR or a transmit enable. It would be only meaningful when connecting to a RS485 bus. If the DTR pin is intended as transmit enable for an optional RS485 transceiver connected to the device, you can simply ignore it.
 

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