... peripheral interface, 2 USB interface, and a RFID external antenna connector, the convenient user according to the need to add ... charge USB1.1 interface host interface (2) RFID module antenna external interfaceKey: Power key, small voice control key, ... +20.7dBmRead-write Distance: 0-3MeterAntenna:Line polarization PCB antenna (1 dbi), standard configuration) or external antennaAudio function parameters ...