This document addresses the provision of ‘Emergency messaging system/eCall’ using the TARV framework, architecture and communications methodology (as defined in ISO15638‑1 to6) and specifies the form and content of such data required to support such systems, and access methods (3.1) to that data. This document provides specifications (3.40) for common communications and data exchange aspects of the application service (3.3) ‘Emergency Messaging System/eCall’ that a regulator (3.28) may elect to require or support as an option, including: High level definition of the service that a service provider (3.38) has to provide, (The service definition describes common service elements; but does not define the detail of how such an application service (3.3) is instantiated, not the acceptable value ranges of the data concepts defined) Means to realise the service Application data, naming content and quality that an IVS (3.23) has to deliver. The definition of what comprises a ‘regulated’ service is regarded as an issue for National decision, and may vary from jurisdiction (3.27) to jurisdiction. This document does not impose any requirements on nations in respect of which services for regulated commercial freight vehicles jurisdictions will require, or support as an option, but provides standardised sets of requirements descriptions for identified services to enable consistent and cost efficient implementations where instantiated. The ISO15638 suite of standards has been developed for use in the context of regulated commercial freight vehicles [hereinafter referred to as regulated vehicles (3.36)]. There is nothing however to prevent a jurisdiction extending or adapting the scope to include other types of regulated vehicles, as it deems appropriate.