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.
IceHook provides modular, cloud based applications to telecom service providers that: manage rates, automate the offsite storage of CDR''s, and provide near real time routing analysis.