A:AnswerHi - The CS6114 and CS6124 are non-expandable. Both base units can be plugged in on the same line as extension units as long as they are connected on an active phone jack/modem. Thank you.
A:AnswerLarry - CS6114 does not feature an answering system. Perhaps you have VOICEMAIL service from your provider, in which case, you would need to contact the provider for assistance.