Some telephones, depending on the brand and model, have the intercom function, which allows to begin communication by sending the signal. When the signal comes, the telephone set rings a signal different from the standard ring tone call. After that the telephone temporarily switches off from the telephone line and works as an intercom.
World-Link is an integrated communications provider marketing communications solutions to targeted customer markets by combining networks, applications and value added services with on-line management, self-service and support.