This battery pack 48V 260Ah 12Kwh Li-ion Batteries is for solar, wind power, UPS and so on. RJ11 for RS232. The protection including Over Charge Protection, Over Discharge Protection, Over Current Protection, Over Temperature Protection, Short Protection.About this battery push, Push the RST (with a pin) for 1 second, LED will turn on one by one to indicate the power on. Push the RST and hold on , the LED will turn off one by one to indicate the power off (can only release the RST after all LED turn off). One LED equal about 25% SOC. 1 LED for : 0%~25%; 2LED for 25%~50%; 3LED for 50%~75%; 4 LED for 75%~100%. Communication connectors is RJ45 for RS485.Before using and handling the pack, see carefully attached “Handling instruction for rechargeable lithium ion battery pack”, for safety reason rechargeable batteries are not shipped in a low remaining capacity state. Charge before using.