If you buy new extensions from Vtech, eBay or BestBuy or wherever you can find them, take the charged battery from your single existing phone and put it in the new phone. It will ask for numbers off the bottom of your base and will then connect as handset2. According to Vonage's help forums, the bases are all the same and all can handle 4 cordless phones. The -1, -2 etc. simply indicates how many cordless phones come with that package.
But I want to configure a handset that I already have from one system to the base of another system. I need to know how to reset the handset to be able to get the option to associate it with another base.
It's in the directions from vtech. I got for 4 with the bases and reprogrammed one base for voicestick for use with all 4 handsets. $5 per Vtech X 4 $5 to voicestick for 1000/out going minutes was free incoming $25 for the whole package on a $28 Amex gift card.
So how do you reprogram the handset. I have looked for instructions online and at VTech and there are not any instructions for reprogamming them. I have found instructions for how to add a new handset, but not how to reprogram/reconfigure.