Interface 4xUSB2.0 ,1x10/100M self-adaption RJ45 interface ,1xUSB2.0 OTG, 1xHDMI, 1xaudio port Touch screen High Quality Capacitive Touch Screen Serial ports 2xSerial ports OS Android4.2.2/Android4.4.2 TF Card Yes Microphone Built-in Frequency Built-in 2W loudspeaker Built-in (optional) 2xUSB2.0, POE power supply, keyboard port, 4xI/O ports, 1xI2C Signal Input Video: Analog Signal/ Sync: TTL Audio Out 0.5W(MAX) (optional) http://www.ksaiandroidpos.com