An integrated security and communications system combines a security system to either or both of a telephone system interface and a data interface. Data functions such as electronic mail and possible partial or full World Wide Web access may also be provided at keypads of the security system, as well as at connected personal computers or computer terminals. The system keypads may be enhanced to better accommodate some of the added functions. A central communications station could be used to maintain secure, shared private key encrypted communications with each premises system, using a redirector arrangement or relay to allow each premises system to communicate securely with a central monitoring station and with other systems. The secure communications system could be used without a security system to allow secure computer-to-computer communications.