Please keep in mind that the provided 12V power adaptor is supposed to operate in 110-240V AC, right?
Why does Linksys SPA ATA 5V adaptors operate at either 110V or 240V of AC mains without any problem of AC hum encountered when they came with Linksys ATA?
I believe the engineers in OBiHai can easily check whether there has AC hum when an ordinarly analogue phone is connected to OBi110 if the input AC votage is 240V.
I am not asking for an replacement, I want to OBi110 to be perfert for applied input AC voltages (110V, 240V) since I am planning to buy OBi110 more in the future. Also many friends of mine are introduced by me to buy many OBi110s for their applications. We have forum (www.telecom-cafe.com) in Chinese and English to discuss how to use OBi110.
In fact, I have used many Linksys ATAs such as SPA1001, SPA PAP2T, SPA 3000, SPA941 such that I am able to tell you the differences very easily if the AC input voltage is 240V.
Only 1US dollar increased in 12V power adaptor, the performance of OBi110 operates at 240V can be improved significantly. Please consider for the next production.