The system of interconnections (20) for external functional blocks on a chip provided with a single configurable communication protocol, comprises two physically separate communication networks (21, 22): a request network (21) for transmitting request messages from an initiating block (23, 24, 25, 26) to a recipient block (27, 28, 29, 30, 31) and a response network (22) for transmitting response messages from a recipient block (27, 28, 29, 30, 31) to an initiating block (23, 25, 26). The response messages include additional information making said request (21) and response (22) networks able to respectively manage the request messages and the response messages independently.