In LINE -INTERACTIVE UPS, sensitive loads supplies from Bypass line, if the by pass line`s supply is cut off or its voltage out of the allowed range, inverter path will be replaced. In normal operation, any disturbance which occurs in the Bypass voltage allowed range, will be transmitted to the load. In normal conditions, battery charger continuously operating to prepare the batteries. In some UPSs, the inverter may be turned off to increase the overall efficiency of the device, although for the inverter fast operation its electronic control components always are active. If the Bypass voltage is lower than the minimum, the inverter will immediately start to operate and the load will be transmitted to the inverter by a static switch (or output relay). As regards the transmission steps begin after the Bypass voltage outage, the inevitable interruption occurs in the supply of load energy, although this short interruption takes 2 to 10 milliseconds. In Line – Interactive system, most of the loads without being damaged, will pass this time and after the main power situation gets normal, the load will be transferred back to Bypass line. Line Interactive UPS try to improve operation better than the off-line by adding a voltage regulator in the Bypass line. In this type of UPS, due to the addition of the voltage regulator circuit in the Bypass line, the load is less connected to the inverter. This system has a low cost and more battery life than Off-Line. Borna niroo karan (Bornika) company is the agent UNIKA company in the fields of consultation, sales and distribution of power industry products including UPS is active.