ISO/IEC ISP 10611-1:2003(E) contains the overall specifications of the support of MHS Elements of Service and associated MHS functionality which are generally not appropriate for consideration only from the perspective of a single MHS protocol. These specifications form part of the Common Messaging application functions, as defined in ISO/IEC ISP 10611 (all parts), which form a common basis for content type-dependent International Standardized Profiles for MHS that will be developed. Such specifications are in many cases applicable to more than one MHS protocol or are otherwise concerned with component functionality which, although it can be verified via protocol, is not just related to protocol support. They are therefore designed to be referenced in the MHS Common Messaging application profiles ISO/IEC ISP 10611-3 (AMH11), ISO/IEC ISP 10611-4 (AMH12 and AMH14), ISO/IEC ISP 10611-5 (AMH13) and ISO/IEC ISP 10611-6 (AMH15), which specify the support of specific MHS protocols and associated functionality.

The specifications in ISO/IEC ISP 10611-1:2003(E) cover the provision and use of features associated with the Message Transfer (MT) Service (MTS), together with those features associated with intercommunication with Physical Delivery (PD) Services. Features which are associated with the Message Store (MS) and User Agent (UA) which are content type-independent are also covered. Features which are specific to a particular content type (including the provision of services by a UA to an MHS user) are covered in separate content type-dependent ISPs.

The specifications in ISO/IEC ISP 10611-1:2003(E) are divided into basic requirements, which are required to be supported by all MHS implementations, and a number of optional functional groups, which cover significant discrete areas of related functionality which are not required to be supported by all implementations.