This document supports provision of data communications in all operational environments e.g.@ continental@ oceanic@ and surface in support of provision of air traffic control services. This document retains the operational@ safety and performance requirements that were specified in legacy SPR documents: operational@ safety@ and performance requirements for data link services that support ATM Operations in oceanic and remote airspace as specified in ED122/DO306 (including Change 1) operational@ safety@ and performance requirements for data link services that support ATM Operations in domestic airspace as specified in ED120/DO290 (including Change 1 and 2) In addition to these legacy data link services@ this document establishes the operational@ safety and performance requirements for additional data link services that support ATM Operations in continental@ oceanic and surface airspaces (see ??.4.4). Note:1. The document scope is limited to the requirements for operational data communications services relevant to the air traffic services. Assumptions for the environment and other ATM operations are stated when necessary to establish the operational requirements and/or the safety and performance requirements for the data communications services contained in this document. 2. This SPR standard is intended to provide the basis for demonstrating that an implemented system@ considering its inherent design and technologies@ can meet the relevant operational@ safety@ and performance requirements for the data communications services described in this document. It is not intended to limit the use of an implementation only to the data communications services and operational context defined herein. However@ in cases where this SPR standard is intended to support additional or to define new data communications services@ the operational@ safety and performance requirements for such operational contexts and/or new data communications services will need to be established as a basis for approval qualification of the implemented systems. 3. Requirements related to securing data communications services that would provide for protection against malicious or intentional behavior causing harm are beyond the scope of this document. 4. Requirements related to the recording of data communications for accident/incident investigation are beyond the scope of this document. Purpose This document defines and allocates the set of minimum requirements for the operational@ safety@ and performance aspects for implementations of data communications services supporting ATS. Allocation is done by this SPR standard to the necessary elements of the CNS/ATM system. This SPR standard is intended for use with interoperability requirements (INTEROP) standards@ and the guidelines described in RTCA DO-264/EUROCAE ED-78A. Note: Based on RTCA DO-264/EUROCAE ED-78A@ INTEROP and SPR standards provide recommendations intended for government organizations@ conference of governments@ or agencies having statutory jurisdiction over the use and provision of data communications services. These recommendations are for use by such government organizations to enunciate official policy related to such matters in aeronautical information publications (AIPs)@ notices to airmen (NOTAMs)@ airplane flight manuals (AFMs)@ and operator specifications.