A:Answer Erik - You can get the model VTech CS5129 and plug it on the same line so they can work as extension units. You can also deregister the handsets of the VTech CS5119-2 and register them to the VTech CS5129 telephone base. For more details, you can contact our Customer Support at 1-800-595-9511. We are open from 9:00 AM to 3:00 PM, Mondays through Fridays.
Thank you,
-VTech Support