Using the ELCOM BTI-256 telecomms interface and an off-the-shelf VoIP adapter (e.g. PAP2T from Linksys®) you can greet visitors from within the house on the Intranet or from anywhere in the world through the Internet.
The door call is fed into the Intranet or Internet. Your SIP provider then transmits the connection to the telephone number you specify. With your multimedia PC (e.g. laptop), an SIP telephone, mobile phone or landline, you can now speak directly to your visitor.