VOIP Service Providers Residential
Media Market Co.
SuperLink Communications Co. Ltd
SuperLink Communications Co. Ltd
Next Telecom palvoip.net
*Next Telecom palvoip.net
Jinan Telecommunication
Jinan Telecommunication
Madar Communication CO
Fusion Co.
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.
