UartSBee V4 - No TX/RX loop possible

I am using two UartSBee V4 together with Xbee Pro modules. In general radio transmission from one to the other module is working correctly. But what I would like to do now is to send some test data across the radio link to the receiving Xbee and then in a loop back to the first module. The first (transmitting) UartSBee is connected via USB to my PC. At the receiving UartSBee I have connected TX and RX of the 6pin UART together.

This receiving module gets 3.3V power at the 3v3 pin of the UART, or alternatively via a USB connection. When I send data from my PC, the LEDs on both modules are flashing, but the data is not looped back to the first module.

So I am not sure, whether this configuration can work at all?

BTW, if I feed a single UartSBee (without Xbee) with data across a connected USB cable, the TX/RX loop is working correctly.

Thanks in advance for help.

When you plug the xbee onto the UartSBee , the serial port of UartSBee will be occupied by xbee. they are communicating, (Tx-Bee_Rx,Rx-Bee_Tx),at the same time, you PC wanna communicate with UartSBee, but sorry, UartSBee is busy now, so the data from the PC can’t be delivered to UartSBee. :laughing:

I’m sorry , maybe this is the fact.