Yes, each voip.com residential phone adapter is capable of providing up to two (2) separate phone lines. Calls from your second, additional line will be separated and included in your monthly bill. Additionally, the service plan you choose for your second line is completely independent of your primary line.
This means that you can choose the most appropriate plan for your needs and your budget. With plans starting at just 9.95 per month, a second line can be a very affordable addition. If you want two lines, start by signing up for just one line, and then purchase a second line by clicking on Add-Ons in your user console.