This part of IEC 61097 specifies the minimum operational and performance requirements, technical characteristics, methods of testing and required test results for INMARSAT F77 ship earth stations (SES), capable of transmitting and receiving distress and safety communications, initiating and receiving distress priority calls and transmitting and receiving general radiocommunications, using radiotelephony (voice), as required within Regulation IV/10.1 and 14.1 of the 1988 amendments to the 1974 International Convention for the Safety of Life at Sea (SOLAS), for use in the GMDSS. The INMARSAT F77 is intended to meet the voice requirements of IMO Resolution A.888(21). In order to meet the GMDSS carriage requirements of SOLAS in respect of receipt of SafetyNET broadcasts and direct printing telegraphy, it is necessary to install a combined INMARSAT C/EGC transceiver in addition to the INMARSAT F77 equipment. Annex B provides more information. Since Class 1 INMARSAT A and B ship earth stations meet the data requirement of GMDSS, although not necessarily those of MSC.130(75), the F77 cannot necessarily be considered as a direct replacement for these ship earth stations. This standard also takes into account the priority access (voice pre-emption) requirements of IMO Resolution A.888(21). This standard takes account of IMO Resolution A.694(17) to which is associated IEC 60945. When a requirement in this standard is different from IEC 60945, the requirement in this standard shall take precedence. This standard incorporates the performance standards of IMO Resolution MSC.130(75) and the clarifications of certain requirements in IMO performance standards for GMDSS Equipment defined in IMO MSC Circular 862. It also incorporates the relevant ITU Radio Regulations. All text of this standard, whose wording is identical to that in the IMO SOLAS Convention 1974 as amended, IMO Resolutions and IMO MSC Circular 862, is printed in italics and the Resolution or Recommendation and paragraph number indicated between brackets. It is a requirement of INMARSAT Ltd that all INMARSAT F77 mobile earth station models be type-approved by INMARSAT before they can be allowed access to the INMARSAT space segment. This testing is designed to demonstrate that the equipment under test will be compatible with the INMARSAT F77 system and will not cause interference to other satellite users. It is recommended that approval authorities accept testing organized and supervised by INMARSAT, which results in INMARSAT type approval, without additional testing other than that defined in this standard. It is also recommended that equipment manufacturers rationalize the test requirements of this standard and those of INMARSAT before embarking on the approval process. NOTE This standard does not incorporate the INMARSAT system requirements needed for INMARSAT type approval. For these, the latest edition of “INMARSAT mini-M SDM Change Note No. 65” should be consulted. When a requirement in this standard is different from one in the above-mentioned INMARSAT document, reference shall be made to the most recent IMO and ITU applicable documents to resolve the difficulty.