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.
Oblcom Swiss AG delivers global services of voice wholesale since 2006. Our business priority is guaranteed fax/CLI/roaming termination via direct routes.