This document defines an additional data concept that may be transferred as an ??optional additional data concept?? as defined in EN 15722 eCall MSD@ that may 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 simply to enable the existing MSD to house multiple OADs. This is achieved by providing a short optional additional data concept@ which facilitates the inclusion of multiple additional datasets within the currently defined MSD of 140 bytes (Every OAD still requires its own specification). 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. See www.esafetydata.com for an example.