The Gigaset S850A GO is a telephone on which you can be reached in 2 different ways: via the analog network of your landline, and via internet telephony, so-called VoIP. If you want to use internet telephony, you must set up 1 or more SIP accounts. The possibilities for this depend on your provider. The S850A GO allows you to set up 6 SIP accounts, each with their own phone number. This phone includes 3 answering machines, which can record up to 55 minutes of messages. You can expand the Gigaset S850A GO with up to 6 handsets, so that you can be reached in every room of your house.