I am trying to establish serial communication with SparkFun LoRaSerial 915 MHz radios. One is connected via USB C and working properly. The other radio is connected with the 6 pin JST. The 5V source and ground have been verified using a multimeter. The RXI pin is connected to the TXD wire and the TXO pin is connected to the RXD wire of the serial cable. This spliced cable is then connected to a serial to USB adapter that is also verified to be working. When opening a serial monitor to both ports, there is no communication between the two. I am able to access the AT commands on the USB C radio. On the JST connected radio, there is no access to AT commands or any communication between radios. Any suggestions?