Question about inverter transfer switch

You could be referring to the main transfer switch for the shore power, mine makes a click that can be heard. My understanding is that keeps shore power isolated from the on board power sources. There is also a transfer switch inside the inverter/charger. I found on the Freedom 438 that I have that the switch time is 25-40 ms. Like someone else here shared, my HD TV still clicks off but the other stuff I found is staying on. The newer pure sine wave Freedom 3012 has in internal transfer switch speed of only 10 ms which they say is fast enough to not disturb electronics. I have experience on a sailboat with the 3012 and none of the many electronics are disturbed when switching from inverter to genset and back, and the genset is on auto start. I was ready to buy a new 3012 inverter if needed, but using a UPS is a great idea and I have one ordered.