The communication system (1) manages the communications of a plurality of user groups (GF) and authorizes secure communications between members (USER) of the same group (GF). The system comprises a server (SRC) and a plurality of user devices (UD) connected to an Internet-type network (IP) allowing voice communications. Speaker recognition and access authorization means (RL) are included and comprise artificial intelligence means (AI). According to the invention, the system comprises voice signal analysis means producing a scalogram of a speaker's voice signal by means of a discrete wavelet transform followed by a continuous wavelet transform, the scalogram being provided as input to the artificial intelligence means for speaker recognition.