Hi! I recently bought an inverter that connects to a 12 volt battery and gives out 220volts AC current. It is rated at 1200W and it produces modified sine wave. The main question I am trying to solve is: Is it safe to run my laptop and dsl router on this modified sine wave? I have done a LOT of reading online about modified sine wave and I came up with VERY contradicting opinions! Some say it is totally suitable for almost all home appliances that the average user may use it for (including TV, radio, laptop, wireless router, stereo..etc). Others say it is only safe to run very basic things (no electronic circuits), like a light bulb, heater..etc.. Some report that they have used all sorts of electronics (including the things I listed above) on modified sine wave for years with no problems at all.. Others report that they hooked up their laptop and minutes or hours later..poof... it was burned!!! I totally understand the difference between sine wave and modified sine wave (or modified square wave if you wish). I also totally understand that pure sine wave is much better (because it is what ideally electronics were designed to work on)... But this is my situation: I already bought the inverter. I live some place where they don't have pure sine wave inverters... I have a LOT of periods where there is no electricity (sometimes for up to 4 hours at a time). And I REALLY need to use my laptop and wireless dsl router and to charge my phone.. Before reading about the topic (when I first bought the inverter a few days ago), I just plugged everything into the inverter and everything (laptop, a desk lamp, my wireless router, my cell phone charger) all ran PERFECTLY normally (as they do on regular electricity).. No difference in performace at all. I would say, I have run them for at least 10 hours (2 or 3 hours at a time) and I have checked the adapters/transformers (the thing that transforms from 220V ac to the DC that the various items require) (specifically my laptop adapter which transforms from 220v AC to 19V DC, my wireless router adapter 220v AC to 22V DC and my phone charger... ) I have periodically checked them and they do not seem to be any hotter than they normally are when I use them on normal AC power (from the grid). I also used a multimeter to check the DC voltage that is coming out of each of them, and it is identical whether using sine wave AC (from the grid) or modified sine wave (from my inverter).. Also I put them to my ear to see if there is any buzz on modified sine wave... Only the laptop adapter (transformer) gave off a very low buzz, but I actually had to put it against my ear to hear it, so it is very low. I also read that some sound equiptment will have 'noise' if run off a modified sine wave.. I did the following experiment: I hooked up a radio and I got the following results: If the radio is attached very close to the inverter there is some noise, however, when I put a long extension cord and then plugged in the radio (so the radio was physically far away from the inverter) it didn't have noise (same level of 'static'/noise on modified sine wave from inverter and on sine wave from the grid)... So after presenting my case, can I assume that I can safely run these items (router, laptop, charger) off the modified sine wave inverter? Again I repeat, getting a true sine wave inverter is not an option for me, so either I use my current one or I sit in the dark and wait for the electricity to come. Also, if I decide to run any other appliance of the modified sine wave, how do I know it is safe? Can I use the following logic (which I used above): If it is not heating up and not producing any weird noises, and is functioning correctly, can I assume it is safe to run it off the modified sine wave inverter? I would truely appreciate any information you could provide me.