Grandstream Mini 286 is the name on SipHardware. It is native name should be HandyTone 286 Analog Telephone Adaptor from its manufacturer.
When use this adaptor with VOIP service, just link it to your internet port by RJ45 and the other RJ11 port to your regular phone set.
You don’t need setting it yourself, if you buy it from the VOIP services provider.
This one is the most cheapest adaptor in the market, but still need US$59.99 plus fees.
I think if the price drop to around $20.00, more users will buy it and use the VOIP services.