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I'm trying to establish a full-duplex and then a half duplex communication and need to wire a device output to an RS485/422 to RS232 converter.

Here is the device output pins for full and half duplex modes: enter image description here

And here is the RS485/422 to RS232 converter screw pins(DATA+ DATA- are for RS485 rest TXs and RXs are for RS422 manual says):

enter image description here

I have 3 questions here.

1-) Is my wiring below from the converter to the device correct for full-duplex?

RS422(FULL DUPLEX)

TX+ <-----> RXD+

TX- <-----> RXD-

RX+ <-----> TXD+

RX- <-----> TXD-

2-) Here is most confusion at half-duplex wiring. Converter shows D for RS485, device shows another notation such as TXD. Here I don't get why they use TXD-/RXD- format for half-duplex. Why both shown? Anyway is my wiring below from the converter to the device correct for half-duplex?

RS485(HALF DUPLEX)

D1+ <-----> TXD+

D1- <-----> TXD-

3-) And finally can I use the half-duplex mode with RS422 full-duplex wiring without wiring back for RS485?

manuals are here: device and converter

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closed as off-topic by Michael Karas, Daniel Grillo, Chetan Bhargava, Dave Tweed Dec 4 '14 at 20:25

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Michael Karas, Daniel Grillo, Chetan Bhargava, Dave Tweed
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1) Yes this is correct.

2) In half duplex, rx and tx data streams both share the same pair of wires so you have rx/tx+ and rx/tx-, otherwise known simply as + and -, or B and A (or confusingly some manufacturers call them A and B). So your wiring as shown is correct.

3) On many devices you can simply loop the rx+,tx+ terminals together and rx-,tx- terminals together for half duplex mode (RS485), but the device must support this.

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