Control R810Pro relay controller with Arduino using RS232 to TTL converter

I have three R810Pro relay boards that I typically use with USB to Serial converters, and all work fine. I have been experimenting with controlling the boards over Bluetooth and WiFi using an Arduino Uno and RS232 to TTL adapter. I can send data through the Arduino/RS232-to-TTL adapter to another com port on my PC with no problem. However, I cannot get the R810Pro to receive any commands through the same system. Therefore my RS232-to-TTL set up is working, but the signals are not received by the relay controller. I am using NCD Base Station to connect to the Arduino COM port, but NCD Base does not see the R810Pro controller through the RS232 to TTL setup.

When connected directly to a com port (USB to serial or a native COM port), the second LED flashes as data is received. When connected to the RS232 to TTL setup, the second LED never flashes.

Any thoughts on this matter would be appreciated. I am wondering if the RS232 to TTL adapter (Max3232) has too low of current to drive the serial communication.

Try moving the PC/MAC jumper.

OK, got it working. Looks like a wiring configuration issue on my part. The serial connection from Arduino/FDTI/microcontroller to the RS232-to-TTL converter must be Rx-Rx and Tx-Tx and then the connection from the converter to the device (R810Pro) must be Rx-Tx and Tx-Rx. I did have the R810Pro set to MAC, and it will not work on the PC jumper setting. Output jumper must be in TTL.