This Recommendation describes the general principles and operational aspects of the voice-mail store-and-forward service defined in Recommendation F.472 when operated and interconnected between service providers. It also addresses the elements of service offered by Voice-mail Store-and-Forward Units (Voice SFUs) to its direct user, a voice-mail system and between Voice SFUs. This service is designed to be implemented in conjunction with Recommendation F.472 which describes the voice-mail store-and-forward service.