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What Terminals are used when connecting the 485LDRC9 for RS-485 or RS-422?

April 26, 2017RS-422 RS-485 terminals Used

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What Terminals are used when connecting the 485LDRC9 for RS-485 or RS-422?

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Refer to Figures 1 to 4 for the most common connections. RS-232 Connections start at Figure 5. RS-232 Connections Figures 1 to 4 show terminal block connections to the DB9 connector of a computer, but the DB9 female connector on the 485LDRC9 will make the same connections using a straight through DB9F to DB9M cable. If the device is wired like a modem as DCE, then pins #2 & #3 must be cross-connected (swapped). The DB9F connector also includes loopbacks for DTR/DSR and RTS/CTS. Measure the DC voltage on pin #3 relative to pin #5, if none, measure pin #2. If pin #2 has voltage, a crossover connection is needed to use the DB9. Many common installation problems are due to the RS-232 connections being reversed. When the converter has a Transmit LED, if it never flashes, check the RS-232 pinouts/wiring. How to identify which of two lines is the output from the device: Use a DC voltmeter, measure from the ground wire to each of the other two RS232 wires, while the RS232 device is powered up.