This document specifies the minimum requirements for aspects related to operation, construction, documentation, methods of testing and required test results for ITU-R M.2135 AMRD Group A man overboard (MOB) devices intended for alerting and locating purposes, as defined by IMO and in accordance with ITU-R M.493 Class-M. This document consists of three modules where the first module, Module A, covers general requirements and aspects. Further Module B covers AIS technologies and Module C covers DSC technologies that are required within MOB equipment. This document incorporates the technical characteristics included in applicable ITU recommendations. Where applicable, it also takes into account the ITU Radio Regulations. This document takes into account other associated IEC international standards and existing national standards, as applicable. This document defines the requirements for coexistence of AIS and DSC technology incorporated within a single equipment.