This document defines an additional data concept that can be transferred as the optional additional data part of an eCall MSD, as defined in EN 15722, that can be transferred from a vehicle to a PSAP in the event of a crash or emergency via an eCall communication session. The purpose of this document is to provide means to notify the PSAP of any limitations to the sending equipment that are endorsed by other standards, but not (immediately) apparent to the receiver. Lack of knowledge about these limitations can hamper the emergency process. This document describes an additional data concept which facilitates the inclusion of information about such limitations in a consistent and usable matter. This document can be seen as an addendum to EN 15722; it contains as little redundancy as possible. NOTE 1 The communications media protocols and methods for the transmission of the eCall message are not specified in this document. NOTE 2 Additional data concepts can also be transferred, and it is advised to register any such data concepts using a data registry as defined in EN ISO 24978 [1]. See www.esafetydata.com for an example.