BPC-7971 User's Manual20Connect system power LED cable with these pins.(pin 1 is LED anode)When system ispower on, power LED is on;when system is power off, power LED is off.2)HDD Status LED Pins(Pin3、4 for HDD LED)There is one HDD LED on panel. When HDD is reading and writing, the LED flashes,indicating the device is working. Connect the HDD status LED cable to the pins. (Pin3 is LEDanode).3)Speaker Pins(Pin 5、6 for SPEAKER)Connect external speaker.4)Reset Button Pins(Pin 7、8 for RESET)Connect the reset button connecting cable connected to the pins. Once system fails andcannot continue with its work, reset button enables the system back to work, without turning offor on the power, so as to prolong the product life span.5)Power On/Off Pins(Pin 9、10 for POWER BUTTON)These two pins are connected to the bounce switch on chassis, to connect or disconnect powersupply.2.5.11 Memory SlotBoard provides 1xPCIE X4 port , 1xon board 4GB/8GB DDR4 memory chip+1x DDR4DIMM slot,memory slot up to 16 GB,the whole board up to 24GB.2.5.12 Expansion PortProvide 2xMINI PCIe slot,one support MSATA/WIFI,the other supportMSATA/WIFI/3G/4G.2.6 Instructions for installation and use of 4G module2.6.1 Install mobile card, 4G module and module antenna on the motherboard。