How do I connect the RP350x reader to my device? Make sure the reader is charged. Plug the RP350x into the audio jack of your device. If you have connected the reader for the first time, ROAMpay X4 will take a few seconds to configure your new reader. After the reader is successfully connected, you will see the ‘connected reader’ icon on the app’s header: For additional support, please refer to the Support Page in your merchant portal or contact your ISO contact.