how do you select between 4 wire rs-422 and 2 wire rs-485 with this device? the circuit board is marked such that it looks like it can do either one but it is lacking the dipswitches or jumpers that similar devices have.

Question

how do you select between 4 wire rs-422 and 2 wire rs-485 with this device?  the circuit board is marked such that it looks like it can do either one but it is lacking the dipswitches or jumpers that similar devices have.

Accepted Answer

The appearance of this product adopts DB-9/DB-9 universal adapter plug.The output interface is equipped with ordinary terminals, and it can use twisted pair or shielded wire. The connection and disconnection are very convenient. The wiring principle is: "send +" connects to the"send +" of the other party, and "receive -" connects to the"send -" of the other party.When connecting in the RS-485 half-duplex mode, connectT/R+ to the A+ of the other device, and T/R- to the B- of theother device.
When connecting in the full-duplex mode of RS-422, connect T/R+
(Transmit+) Receive the RXD+ from the other party(Receive+), T/R-(Transmit-)receive the RXD from the other party (Receive-), RXD+ (Receive+) receive the TXD+ from the other party (Transmit+), RXD(Receive-)
Receive the TXD- (transmit) signal from the other party.

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