A system architecture configured to dynamically open communication channels of optimised dimension with guaranteed bit rate, the communication protocol used being the RTP protocol, said system architecture being intended to be positioned in an aircraft, a suitcase and/or a ship, and/or a ground station comprising one or more voice-over-IP terminals Ti, said architecture comprising at least the following elements: • a satellite communication system of BGAN, SwiftBroadband or FleetBroadband type, an IP data terminal configured to transmit data to a router comprised in the architecture and an IP voice terminal configured to communicate in parallel with a SIP server for the signalling and the RTP stream, • said ground or on-board SIP server comprising at least the following elements: ∗ a rate adapter module located between at least one sender terminal T 1 and a receiver terminal T 2, said rate adapter module being a software function carried by the SIP server configured to control, clock and adapt the rate of an RTP stream received by a terminal, ∗ a control module of SIP signalling present in the data stream in order to control and modify the RTP port numbers and the coder-decoders implemented by the data terminals, T 1, T 2, said control module comprising a signalling interception module and a signalling modification module, said signalling interception module being configured to receive the information from a data transmitting terminal and an access control module, • the rate adapter module being a module configured to allow adaptation of a G.729 low bit rate codec to the G.711 codec and vice versa. • a satellite communication system of BGAN, SwiftBroadband or FleetBroadband type, an IP data terminal configured to transmit data to a router comprised in the architecture and an IP voice terminal configured to communicate in parallel with a SIP server for the signalling and the RTP stream, • said ground or on-board SIP server comprising at least the following elements: ∗ a rate adapter module located between at least one sender terminal T 1 and a receiver terminal T 2, said rate adapter module being a software function carried by the SIP server configured to control, clock and adapt the rate of an RTP stream received by a terminal, ∗ a control module of SIP signalling present in the data stream in order to control and modify the RTP port numbers and the coder-decoders implemented by the data terminals, T 1, T 2, said control module comprising a signalling interception module and a signalling modification module, said signalling interception module being configured to receive the information from a data transmitting terminal and an access control module, ∗ a rate adapter module located between at least one sender terminal T 1 and a receiver terminal T 2, said rate adapter module being a software function carried by the SIP server configured to control, clock and adapt the rate of an RTP stream received by a terminal, ∗ a control module of SIP signalling present in the data stream in order to control and modify the RTP port numbers and the coder-decoders implemented by the data terminals, T 1, T 2, said control module comprising a signalling interception module and a signalling modification module, said signalling interception module being configured to receive the information from a data transmitting terminal and an access control module, • the rate adapter module being a module configured to allow adaptation of a G.729 low bit rate codec to the G.711 codec and vice versa.