You will need to ensure you are using the same radio. 400Mhz or 900Mhz. If the A631 is set up for WEBUI and is connected to a 900Mhz radio, use your phone or laptop to connect to the A631 and change the Port B baud rate to 115200. Detecting the radio and setting the radio channel with the WEBUI will set the necessary baud rates on both the radio and the antenna. If it is not set up for WEBUI, you will need to connect to the A631 and radio with a USB to serial cable and data cable and set the antenna Port B and radio port baud rates to 115200. If it is running a 400Mhz radio, you will connect to the A631 and radio with a laptop and USB to serial cable and a data cable to change the Port B baud rate to 115200 on both the antenna and the radio. If the A631 is running WEBUI and has a 400Mhz radio, you will still have to connect to the radio separately to change the radio port baud rate to 115200. You will need the PockeMAX software for any changes not made with the WEBUI. If there is still no connectivity, change the A321 baud rate to 115200 as well.