Communication system comprising at least one unit referred to as a telephone intercom unit, which is capable of communicating video and audio via telephone lines with a remote unit, the system also comprising at least one unit forming an intermediate server, characterised in that communication between the unit and the remote unit takes place directly solely for voice communication via GSM; and the at least one intermediate unit, comprising a video server, receives video data from the unit and transmits said data to the remote unit when direct voice communication has been established between the unit and the remote unit, the unit, after accepting a communication with the unit, connects via a 4G DATA link to the video server, an HTTPS format connection being established in order to send a request warning of a voice communication between the unit and the remote unit, establish a VPN connection between the unit and the video server, and send a request to the video server to provide the VPN IP address, and other information that might help to recover the video stream from this unit; on receipt of the information at the video server, the VPN connection is identified on the video server as belonging to the call session between the unit and the remote unit, the video server creates a redirection of the VPN IP address of the unit broadcasting the video stream on the video server to a URL address that can be consulted by an application (APP A) installed on the remote unit, the VPN IP address of the unit is stored in a table associated with the unit ID and the voice connection between the unit and the remote unit, the application (APP A) connecting via a 3G/4G/5G DATA link, the video server sending the URL address to recover the video stream to the application (APP A). communication between the unit and the remote unit takes place directly solely for voice communication via GSM; and the at least one intermediate unit, comprising a video server, receives video data from the unit and transmits said data to the remote unit when direct voice communication has been established between the unit and the remote unit, the unit, after accepting a communication with the unit, connects via a 4G DATA link to the video server, an HTTPS format connection being established in order to send a request warning of a voice communication between the unit and the remote unit, establish a VPN connection between the unit and the video server, and send a request to the video server to provide the VPN IP address, and other information that might help to recover the video stream from this unit; on receipt of the information at the video server, the VPN connection is identified on the video server as belonging to the call session between the unit and the remote unit, the video server creates a redirection of the VPN IP address of the unit broadcasting the video stream on the video server to a URL address that can be consulted by an application (APP A) installed on the remote unit, the VPN IP address of the unit is stored in a table associated with the unit ID and the voice connection between the unit and the remote unit, the application (APP A) connecting via a 3G/4G/5G DATA link, the video server sending the URL address to recover the video stream to the application (APP A).