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.
Keyhan Telecom Inc. is a wholesale carrier company that is specialized on termination and origination services for “mobile and landline around the globe. We are a wholesale carrier based in Toronto, Canada.