... USB 1.1 Host,1 Client 1 RS232 serial portbuilt-in mic; Speaker and 3.5 mm stereo headphone jack; ... (optional)supportPower BatteryCharging methodCharging time Rechargeable 3.7V,4000mAH battery Enclosed power supply,separate seat charge5hours Support functionsRFIDBarcode Scaner(ID ... /GPRS/3G ,WIFI,Bluetooth RS232 communication, and optional buit-in barcode scaner , rfid card reader and 37.9Khz infrared ...