Abstract: The installation comprises a remote loading mode in which in response to a remote loading request word (R) for a predetermined number of value units emanating from the autonomous set (PA), there is provided:an active authentication of the autonomous set (PA) and of the access system (SAA);a calculation of a remote loading passkey (KCH or (SCH, PCH)) at the level of the authorization center (CA);a transmission of the enciphered remote loading passkey destined for the access system (SAA);a secure remote loading of the prepayment means (MPAY) originating from the access system with the aid of the remote loading passkey thus transmitted.